How does the number of valence electrons in an atom relate to the element's
placement on the periodic table?
O A. Elements in the same group have the same number of valence
electrons.
B. The number of valence electrons increases as the atomic number
increases
C. The number of valence electrons is the same for all elements on
the periodic table.
D. Elements in the same period have the same number of valence
electrons.
Answers
Answer:
A
Explanation:
Related Questions
In the presence of a strong base, the following reaction between (CH3)3CCl and OH- occurs: (CH3)3CCl + OH- → (CH3)3COH + Cl- Studies have suggested that the mechanism for the reaction takes place in 2 steps: Step 1) (CH3)3CCl → (CH3)3C+ + Cl- (slow) Step 2) (CH3)3C+ + OH- → (CH3)3COH (fast) What is the rate law expression for the overall reaction? Group of answer choices
Answers
Answer:
D. rate = k [(CH3)3CCl]
Explanation:
(CH3)3CCl + OH- → (CH3)3COH + Cl-
The mechanisms are;
Step 1)
(CH3)3CCl → (CH3)3C+ + Cl- (slow)
Step 2)
(CH3)3C+ + OH- → (CH3)3COH (fast)
In kinetics, the slowest step is the ratee determining step.
For a given reaction;
A → B + C, the rate law expression is given as;
rate = k [A]
In this problem, from step 1. The rate expression is;
rate = k [(CH3)3CCl]
Give the characteristic of a zero order reaction having only one reactant. a. The rate of the reaction is not proportional to the concentration of the reactant. b. The rate of the reaction is proportional to the square of the concentration of the reactant. c. The rate of the reaction is proportional to the square root of the concentration of the reactant. d. The rate of the reaction is proportional to the natural logarithm of t
Answers
Answer:
a. The rate of the reaction is not proportional to the concentration of the reactant.
Explanation:
The rate expression for a zero order reaction is given as;
A → Product
Rate = k[A]⁰
[A]⁰ = 1
Rate = K
GGoing through the options;
a) This is correct because in the final form of the rate expression, the rate is independent of the concentration.
b) This option is wrong
c) This option is also wrong
d) Like options b and c this is also wrong becaus ethere is no relationship between either the concentration or t.
need helpp asapp please
Answers
Answer:
B. None of these
Explanation:
Sulfur has less ionization energy than phosphorus because sulfur has a pair of electron in its 3p subshell that increases electron repulsion in sulfur and sulfur electrons can easily remove from its sub-level.
While, there are no electron pairs in 3p subshell of phosphorus, therefore it requires more energy to remove an electron from 3p subshell.
Hence, the reason is electron repulsion and the correct answer is B.
Rank the following transitions in a hydrogen atom in order of increasing wavelength of electromagnetic radiation that could produce them. Answer this question without doing any calculations. Explain the order.
n=2 to n=4
n=6 to n=8
n=10 to n=12
n=14 to n=16
Answers
Answer:
n=2 to n=4 < n=6 to n=8 < n=10 to n=12 < n=14 to n=16
Explanation:
According to Neils Bohr, electrons in an atom are found in specified energy levels. Transitions are possible from one energy level to another when the electron receives sufficient energy usually in the form of a photon of electromagnetic radiation of appropriate frequency and wavelength. The energy of this photon corresponds to the energy difference between the two energy levels. Thus the higher the energy difference between energy levels, the greater the energy of the photon required to cause the transition and the shorter the wavelength of the photon.
High energy photons have a very short wavelength. It should be noted that as n increases, the energy of successive energy levels decreases and transitions between them now occurs at longer wavelengths. Hence, the highest energy and shortest wavelength of photons are required for transition involving lower values of n because such electrons are closer to the nucleus and are more tightly bound to it than electrons found at a greater distance from the nucleus.
Hence transition involving electrons at higher energy levels occur at a longer wavelength compared to transition involving electrons closer to the nucleus. This is the basis for the arrangement of wavelengths required to effect the various electronic transitions shown in the answer.
Of Sr or Ba , the element with the higher first ionization energy is
Answers
Answer:
Sr
Explanation:
Sr has an ionization of 550 whereas Ba has an ionization of 503
all compounds are neutral true or false
Answers
Answer:
Even all compounds are neutral.
Explanation:
Some of them exhibit polarity. Because of the difference in electron affinity of the constituent atoms, the shared electrons are pulled towards the atom with high affinity to electrons.
Among three bases, X−, Y−, and Z−, the strongest one is Y−, and the weakest one is Z−. Rank their conjugate acids, HX, HY, and HZ, in order of decreasing strength. Rank the acids from strongest to weakest. To rank items as equivalent, overlap them.
Answers
Answer: HZ > HX > HY in order of decreasing strengths.
Explanation: Generally, the rule is that the stronger the acid, the weaker its conjugate base and vice versa; same rule applies for bases and their conjugate acids.
So the weakest base Z- would have the strongest conjugate acid. Consequently, the strongest base Y- would have the weakest conjugate acid.
I hope this was MORE helpful as this is the correct answer.
The ranking of the conjugate acids in order of decreasing strength (i.e from strongest to weakest) is; HZ < HX < HY
First we must know that the stronger a base is, the weaker is it's conjugate acid and the weaker a base is, the stronger is it's conjugate acid.
Therefore, the order of decreasing strength of the conjugate acid is; HZ < HX < HY
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A solution of benzene in methanol has a transmittance of 93.0 % in a 1.00 cm cell at a wavelength of 254 nm. Only the benzene absorbs light at this wavelength, not the methanol. What will the solution's transmittance be if it is placed in a 10.00 cm long pathlength cell
Answers
Answer:
T = 48.39%
Explanation:
In this case we need to apply the Beer law which is the following:
A = CεL (1)
Where:
A: Absorbance of solution
C: Concentration of solution
ε: Molar Absortivity (Constant)
L: Length of the cell
Now according to the given data, we have transmittance of 93% or 0.93. We can calculate absorbance using the following expression:
A = -logT (2)
Applying this expression, let's calculate the Absorbance:
A = -log(0.93)
A = 0.03152
Now that we have the absorbance, let's calculate the concentration of the solution, using expression (1).
A = CεL
C = A / εL
Replacing:
C = 0.03152 / 1 *ε (3)
Now, we want to know the transmittance of the solution with a length of 10 cm. so:
A = CεL
Concentration and ε are constant, so:
A = (0.03152 / ε) * ε * 10
A = 0.3152
Now that we have the new absorbance, we can calculate the new transmittace:
T = 10^(-A)
T = 0.4839 ----> 48.39%
When 1-iodo-1-methylcyclohexane is treated with NaOCH2CH3 as the base, the more highly substituted alkene product predominates. When KOC(CH3)3 is used as the base, the less highly substituted alkene predominates. Give the structures of the two products and offer an explanation.
Answers
An experiment calls for 10.0 mL of bromine (d = 3.12 g/mL). Since an accurate balance is available, it is decided to measure the bromine by mass. How many grams should be measured out? Multiple Choice 3.21 32.1 3.12 31.2 0.312
Answers
Answer:
31.2g
Explanation:
The following data were obtained from the question:
Volume of bromine = 10mL
Density of bromine = 3.12 g/mL
Mass of bromine =...?
The Density of the substance is related to it's mass and volume by the following equation:
Density = Mass /volume
With the above equation, we can calculate the mass of bromine as follow:
Density = Mass /volume
Volume of bromine = 10mL
Density of bromine = 3.12 g/mL
Mass of bromine =...?
Density = Mass /volume
3.12 = Mass /10
Cross multiply
Mass of bromine = 3.12 x 10
Mass of bromine = 31.2g
Therefore, the mass of bromine is 31.2g
Use the link Standard Reduction Potentials. Write net equations for the spontaneous redox reactions that occur during the following or none (all lower case) if there is no extensive reaction. Use the lowest possible coefficients. A) Iron metal is dipped into a Ni2+ solution.B) Copper metal is added to hydrochloric acid.C) A silver wire is added to nitric acid (HNO3).D) Magnesium metal is added to waterE) Chromium metal is added to a solution of Mg2+
Answers
Answer:
a) Fe(s) + Ni^2+(aq) ----> Fe^2+(aq) + Ni(s)
b) no reaction
c) no reaction
d) 2Mg(s) + 2H2O(l)-----> 2Mg^2+(aq) + O2(g) +4H^+(aq)
e) no reaction
Explanation:
It is important to say here that the ability of a particular chemical specie to displace another chemical specie is dependent on the relative standard reduction potentials of the species involved.
All the reactions stated above are redox reactions. Let us take reaction E as an example. Mg^2+ has a reduction potential of -2.37 V while Cr^3+ has a reduction potential of -0.74V. Since the reduction potential of magnesium is more negative than that of chromium, there is no reaction when a piece of chromium metal is dipped into a solution of Mg^2+.
Similarly, though metals displace hydrogen gas from dilute acids, metals that are less than hydrogen in the reactivity series cannot do that. This explains why there is no reaction when copper and silver are dipped into dilute acid solutions.
Reaction occurs when iron is dipped into a nickel solution because the reduction potential of Fe^2+ is far more negative than that of Ni^2+.
A piece of wood near a fire is at 23°C. It gains 1,160 joules of heat from the fire and reaches a temperature of 42°C. The specific heat capacity of
wood is 1.716 joules/gram degree Celsius. What is the mass of the piece of wood?
ОА. 16 g
OB. 29 g
ОC. 36 g
OD. 61 g
Answers
Answer:
35.578g or 36g if you round
Explanation:
Q=mc ∆∅ where ∅ is temperature difference
1160= m x 1.716 x (42-23)
m = 1160/ 1.716 x19
m=35.578g
m = 36g to nearest whole number
Answer: C. 36 g
Explanation: I got this right on Edmentum.
Given the following Fischer projection: Fischer projection for an entantiomer of 2-bromo-2,3-dihydroxypropanal with the bromine oriented horizontally to the left and the hydroxide group oriented horizontally to the right. draw the perspective formula of the molecule. Be sure to correctly indicate stereochemistry in your answer.
Answers
Answer:
Explanation:
Stereoisomers are two or more atoms that have the same bonding order of atoms but there is a difference spatial arrangement of the atoms in space.
A plane of symmetry divides a molecule into two equal halves.
A chiral stereoisomer are not superimposed on a mirror image , Hence they do not posses a plane of symmetry.
As a result to that. these non-superimposable mirror images are said to be Enantiomers.
However, a Fischer Projection emanates from a two - dimensional figure which is used for presenting a three - dimensional organic molecules.
From the given question;
Fischer projection for an enantiomer of 2-bromo-2,3-dihydroxypropanal with the bromine oriented horizontally to the left and the hydroxide group oriented horizontally to the right.
we can sketch the way the enantiomer of 2-bromo-2,3-dihydroxypropanal can be seen like the one shown below:
CH₂OH
|
|
|
Br -------------|----------------OH
|
|
|
CHO
The objective of this question is to drawn the perspective formula of the molecule.
So , from the attached file below; we can see the perspective formula of the molecule in a well structured 3-D format.
A certain mass of carbon reacts with 9.53 g of oxygen to form carbon monoxide. ________ grams of oxygen would react with that same mass of carbon to form carbon dioxide, according to the law of multiple proportions.
Answers
Answer: 9.53 *2= 19.06
Explanation:
The law of multiple proportions states that if two elements combines to form more than one compound the ratio of masses of the second element which combines to the fixed mass of the first element will always be the ratios of the small whole numbers.
in case of carbon monoxide, mass of carbon will be the same of mass of oxygen.
But in case of carbon dioxide, if carbon is 9.53 units then oxygen will be twice as that of carbon.
CO2, so 9.53*2= 19.06 grams of oxygen will combine with 9.53 grams of carbon to form carbon dioxide.
The volume of a sample of water is 2.5 mL the volume of the sample in liters is
Answers
Answer:
0.0025Litters
Explanation:
2.5ml= 2.5x10^-3l
2.5ml= 0.0025l
Answer:
AAAAAAAA
Explanation:
What is Key for the reaction 2503(9) = 2802(9) + O2(g)?
Answers
Answer:
Option C. Keq = [SO2]² [O2] /[SO3]²
Explanation:
The equilibrium constant keq for a reaction is simply the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient.
Now, let us determine the equilibrium constant for the reaction given in the question.
This is illustrated below:
2SO3(g) <==> 2SO2(g) + O2(g)
Reactant => SO3
Product => SO2, O2
Keq = concentration of products /concentration of reactants
Keq = [SO2]² [O2] /[SO3]²
A solid is dissolved in a liquid, and over time a solid forms again. How can
you confirm the type of change that took place?
A. Testing the new solid to show that its properties are the same as
the starting solid would confirm that a physical change took
place.
B. The solid dissolving in a liquid is confirmation that a chemical
change took place.
C. The solid forming from the liquid is confirmation that a physical
change took place.
D. Showing that the total mass of the solid and liquid changed would
confirm that a chemical change took place.
Answers
Classify the substances as atomic elements, molecular elements, molecular compounds, or ionic compounds. a. Agb. Cdc. MgCl2d. F2f. HIg. NO2h. NaCli. Cl2
Answers
Answer:
Explanation:
Hello,
We'll be doing some classification of some chemical substances based on molecules, elemental state or ionic or electrovalent properties.
A) Ag = atomic element : silver (Ag) in its elemental state is an atomic element.
B) Cd = atomic element : Cadmium (Cd) is an element of the periodic table and belongs to transition metal.
C) MgCl = ionic compounds: this is a compound formed between magnesium (Mg) and chlorine (Cl) to give MgCl. This compound has ionic or electrovalent properties since electron transfer occurred between the cation (Mg) and anion (Cl).
D) F₂ = moleculer element : Fluorine F₂ is moleculer element since two elements of fluorine combine together to form a molecule.
E) HI = molecular compound : this is a compound formed from the reaction between hydrogen and iodine. It's a molecular compound because they are two different elements combining together to form a compound.
F) NO₂ = molecular compound
G) NaCl = ionic compound
H) Cl₂ = molecular element
What is the law of conservation and what happens when two substances at different temperatures come into contact.
Answers
Answer:
- Both energy and matter cannot be neither created nor destroyed.
- An equilibrium temperature will be reached.
Explanation:
Hello,
In this case, the law of conservation is applied to both matter and energy, and it states that both energy and matter cannot be neither created nor destroyed. Specifically, in chemical reactions, it states that in closed systems, the mass of the reactants equals the mass of the products even when the number of moles change. Moreover, for energy, if two substances at different temperatures come into contact, the hot one will cool down and the cold one will heat up until an equilibrium temperature so the energy lost by the hot one is gained by the cold one, which accounts for the transformation of energy.
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What is an ion?
A. An atom that has lost or gained 1 or more electrons
O B. An atom that has lost or gained 1 or more neutrons
O C. An atom that has lost or gained 1 or more protons
D. An atom that differs in mass from another atom of the same
element
Answers
Answer:
An ion is an atom that has lost or gained one or more electrons.
Explanation:
Ions are positively or negatively charged atoms of elements. This is because they can give, take, or share electrons with other elements to encourage the formation of chemical bonds.
Protons are what decide the chemical identity of the element. So, for example, if an atom has 11 protons, we know that will be a Sodium (Na) atom. A loss or gain of protons completely changes the chemical identity of the element and it will then become another element.
Electrons are what give an atom a neutral electrical charge (if that atom has the number of protons and neutrons normally described for the element - otherwise, a discrepancy or gain in neutrons is referred to as an isotope and declares that ions have nothing to do with the mass of an element).
With this information, you can realize that neutrons and protons have nothing to do with ions and you can confirm that ions are atoms that have lost or gained one or more electrons.
chemical equation for potassium sulfate and lead(II) acetate
Answers
Answer:
K₂SO₄ + Pb(C₂H₃O₂)₂ →PbSO₄ + 2KC₂H₃O₂
A chemical equation is a symbolic representation of a chemical reaction. The chemical equation for the reaction between potassium sulfate ([tex]K_2SO_4[/tex]) and lead(II) acetate ([tex]Pb(CH_3COO)_2[/tex]) can be written as follows:
[tex]K_2SO_4 + Pb(CH_3COO)_2 = PbSO_4 + 2CH_3COOK[/tex]
A basic chemical equation consists of two main parts: the reactant side (left side) and the product side (right side), separated by an arrow indicating the direction of the reaction. Reactants are substances that undergo a chemical change, while products are substances formed as a result of the reaction.
In this reaction, potassium sulfate reacts with lead(II) acetate to form lead(II) sulfate and potassium acetate. It is important to note that the equation is balanced with stoichiometric coefficients, ensuring that the number of atoms of each element is the same on both sides of the equation.
Therefore, the chemical equation for the reaction between potassium sulfate ([tex]K_2SO_4[/tex]) and lead(II) acetate ([tex]Pb(CH_3COO)_2[/tex]) can be written as follows:
[tex]K_2SO_4 + Pb(CH_3COO)_2 = PbSO_4 + 2CH_3COOK[/tex]
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Enter an abbreviated electron configuration for magnesium: Express your answer in complete form, in order of increasing energy. For example, [He]2s22p2 would be entered as [He]2s^22p^2.
Answers
Answer:
[Ne]3s²
Explanation:
Mg
1s2 2s2 2p6 3s2 or [Ne]3s²
Abbreviated electronic configuration of magnesium is [Ne]3 s² and in complete form it is 1 s² 2 s² 2 p⁶ 3 s².
What is electronic configuration?Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
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The reason for the dramatic decline in the number of measles cases from the 1960s to 2010 in the United States was because the vaccine
Answers
Answer:
It was because the vaccine generated actively acquired immunity, that is, inoculation of a portion of the measles virus so that the body forms the antibodies for a second contact and thus can destroy it without triggering the pathology.
Explanation:
Vaccines are methods of active acquired immunity since the antibody is not passively inoculated, it is manufactured by the body with a physiological process once part of the virus is inoculated.
The measles virus most of all affected the lives of infants or newborn children with severe rashes and high fevers that led to death.
Question 1
1 pts
2B+6HCI --
| --> 2BCl3 + 3H2
How many moles of boron chloride will be produced if you start with 8.752 moles of HCI
(hydrochloric acid)? (Round to 3 sig figs. Enter the number only do not include units.)
Answers
Answer:
2.92 mol
Explanation:
Step 1: Write the balanced equation
2 B(s) + 6 HCI(aq) ⇒ 2 BCl₃(aq) + 3 H₂(g)
Step 2: Establish the appropriate molar ratio
The molar ratio of hydrochloric acid to boron chloride is 6:2.
Step 3: Calculate the moles of boron chloride produced from 8.752 moles of hydrochloric acid
[tex]8.752molHCl \times \frac{2molBCl_3}{6molHCl} = 2.92molBCl_3[/tex]
What is the net ionic equation of the reaction of MgSO4 with Ba(NO3)2 ?
Answers
Answer:
Ba(+2)(aq) + SO4(-2)(aq) -----> BaSO4(s)
Explanation:
Take a look at the attachment below;
A solution that is 0.135 M is diluted to make 500.0 mL of a 0.0851 M solution. How many milliliters of the original solution were required? View Available Hint(s) A solution that is 0.135 M is diluted to make 500.0 mL of a 0.0851 M solution. How many milliliters of the original solution were required? 5.74 mL 0.315 mL 793 mL 315 mL
Answers
Answer:
315mL
Explanation:
Data obtained from the question include the following:
Molarity of stock solution (M1) = 0.135 M
Volume of stock solution needed (V1) =?
Molarity of diluted solution (M2) = 0.0851 M
Volume of diluted solution (V2) = 500mL
The volume of the stock solution needed can be obtain as follow:
M1V1 = M2V2
0.135 x V1 = 0.0851 x 500
Divide both side by 0.135
V1 = (0.0851 x 500) / 0.135
V1 = 315mL
Therefore, the volume of the stock solution needed is 315mL
Convert 150 K to degrees C.
Answers
Answer:
K = 150, C = - 123.15°
Explanation:
Kelvin = Celcius + 273.15 / 0 Kelvin = - 273.14 C
_____________________________________
Thus,
150 K = Celcius + 273.15,
150 - 273.15 = C,
C = -123.15 degrees
Solution, C = - 123.15°
Answer:
C=-123.15
Explanation:
This is easy
Please what's the missing minor products? And kindly explain in your own words how they were formed. Thank you!
Answers
Answer:
it's a two step elimination reaction
Explanation:
it follows a carbocationic pathway. When carbocation is stable, the equation is favourable, that is, double bond is formed by expelling hydrogen atom.
The partial Lewis structure that follows is for a hydrocarbon molecule. In the full Lewis structure, each carbon atom satisfies the octet rule, and there are no unshared electron pairs in the molecule. The carbon-carbon bonds are labeled 1, 2, and 3.
A) How many hydrogen atoms are in the molecule?
B) Rank the carbon-carbon bonds in order of increasing bond length.
C) Which carbon-carbon bond is the strongest one?
Answers
Answer:
A) How many hydrogen atoms are in the molecule?
The lock-and-key model and the induced-fit model are two models of enzyme action explaining both the specificity and the catalytic activity of enzymes. Following are several statements concerning enzyme and substrate interaction. Indicate whether each statement is part of the lock-and-key model, the induced-fit model, or is common to both models.
a. Enzyme conformation changes when it binds the substrate so the active site fits the substrate.
b. Substrate binds to the enzyme at the active site, forming an enzyme-substrate complex.
c. Enzyme active site has a rigid structure complementary
d. Substrate binds to the enzyme through noncovalent interactions
Answers
Answer:
The lock-and-key model:
c. Enzyme active site has a rigid structure complementary
The induced-fit model:
a. Enzyme conformation changes when it binds the substrate so the active site fits the substrate.
Common to both The lock-and-key model and The induced-fit model:
b. Substrate binds to the enzyme at the active site, forming an enzyme-substrate complex.
d. Substrate binds to the enzyme through non-covalent interactions
Explanation:
Generally, the catalytic power of enzymes are due to transient covalent bonds formed between an enzyme's catalytic functional group and a substrate as well as non-covalent interactions between substrate and enzyme which lowers the activation energy of the reaction. This applies to both the lock-and-key model as well as induced-fit mode of enzyme catalysis.
The lock and key model of enzyme catalysis and specificity proposes that enzymes are structurally complementary to their substrates such that they fit like a lock and key. This complementary nature of the enzyme and its substrates ensures that only a substrate that is complementary to the enzyme's active site can bind to it for catalysis to proceed. this is known as the specificity of an enzyme to a particular substrate.
The induced-fit mode proposes that binding of substrate to the active site of an enzyme induces conformational changes in the enzyme which better positions various functional groups on the enzyme into the proper position to catalyse the reaction.