The electron configuration of an element is 1s22s2. How many valence electrons does the element have? (1 point) a 1 b 2 c 3 d 4

Answers

Answer 1

Answer:

b

Explanation:the shell is 2 so ignore the 1s electrons it is only the level 2 electrons that are valence


Related Questions

5. If all the particles in a material are made up of
several smaller particles, and every larger particle
is identical, is the material a pure substance or
not? Explain your reasoning.

Answers

Answer:

No. Because a pure substance, no matter if an element, compound, it can only contain one kind of particle .

Explanation:

What is the percent by mass of calcium in calcium carbonate,
CaCO3?
(Molar mass of CaCO3 = 100.09 g/mol)

%

Answers

What is the percent by mass of calcium in calcium carbonate, CaCO3? (Molar mass of CaCO3 = 100.09 g/mol)

Answer: 40.04 percent

The percent by mass of calcium in calcium carbonate ([tex]CaCO_{3}[/tex]) is approximately 40.04%.

To calculate the percent by mass of calcium in calcium carbonate ([tex]CaCO_{3}[/tex]), we need to determine the molar mass of calcium (Ca) and the molar mass of calcium carbonate ([tex]CaCO_{3}[/tex]), and then use the following formula:

Percent by mass of calcium = (Molar mass of calcium / Molar mass of calcium carbonate) x 100

Given:

Molar mass of [tex]CaCO_{3}[/tex] = 100.09 g/mol

Now, let's calculate the molar mass of calcium (Ca):

The molar mass of calcium (Ca) is 40.08 g/mol.

Plugging in the values into the formula, we get:

Percent by mass of calcium = (40.08 g/mol / 100.09 g/mol) x 100

                         = 0.4004 x 100

                         = 40.04%

Therefore, the percent by mass of calcium in calcium carbonate ([tex]CaCO_{3}[/tex]) is approximately 40.04%.

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In each of the following sets of elements, which one will be least likely to gain or lose electrons?

1. Cesium (Cs), Rubidium (Rb), and Sodium (Na)

2. Barium (Ba), Calcium (Ca), and Beryllium (Be)

3. Fluorine (F), Chlorine (Cl), and Bromine (Br)

4. Tellurium (Te), Oxygen (O), and Sulfur (S)

Answers

1. The reactivity among the alkali metals increases as you go down the group due to the decrease in the effective nuclear charge from the increased shielding by the greater number of electrons. The greater the atomic number, the weaker the hold on the valence electron the nucleus has, and the more easily the element can lose the electron. Conversely, the lower the atomic number, the greater pull the nucleus has on the valence electron, and the less readily would the element be able to lose the electron (relatively speaking). Thus, in the first set comprising group I elements, sodium (Na) would be the least likely to lose its valence electron (and, for that matter, its core electrons).

2. The elements in this set are the group II alkaline earth metals, and they follow the same trend as the alkali metals. Of the elements here, beryllium (Be) would have the highest effective nuclear charge, and so it would be the least likely to lose its valence electrons. In fact, beryllium has a tendency not to lose (or gain) electrons, i.e., ionize, at all; it is unique among its congeners in that it tends to form covalent bonds.

3. While the alkali and alkaline earth metals would lose electrons to attain a noble gas configuration, the group VIIA halogens, as we have here, would need to gain a valence electron for an full octet. The trends in the group I and II elements are turned on their head for the halogens: The smaller the atomic number, the less shielding, and so the greater the pull by the nucleus to gain a valence electron. And as the atomic number increases (such as when you go down the group), the more shielding there is, the weaker the effective nuclear charge, and the lesser the tendency to gain a valence electron. Bromine (Br) has the largest atomic number among the halogens in this set, so an electron would feel the smallest pull from a bromine atom; bromine would thus be the least likely here to gain a valence electron.

4. The pattern for the elements in this set (the group VI chalcogens) generally follows that of the halogens. The greater the atomic number, the weaker the pull of the nucleus, and so the lesser the tendency to gain electrons. Tellurium (Te) has the highest atomic number among the elements in the set, and so it would be the least likely to gain electrons.

8.
Sulfur trìoxide decomposes to sulfur dioxide and oxygen gas as
shown in the following reaction:
2503 (g) 2502 (g) + O2 (g)
Given a 240.0 g sample of sulfur trioxide (MM = 80.1 g/mol), how many
grams of oxygen (MM = 32.0 g/mol) are produced, assuming the
decomposition goes to completion?
g
Your answer should be rounded to three significant figures. Do not include units in your
answer

Answers

Mass of Oxygen : 47.9

Further explanation

Given

2S03 (g)⇒ 2S02 (g) + O2 (g)

240 g SO3

Required

mass of Oxygen

Solution

mol SO3 :

= 240 g : 80.1 g/mol

= 2.996

From the equation, mol O2 :

= 1/2 x mol SO3

= 1/2 x 2.996

= 1.498

mass O2 :

= 1.498 mol x 32 g/mol

= 47.9

Taking into account the reaction stoichiometry, given a 240.0 g sample of sulfur trioxide, 47.95 grams of oxygen are produced, assuming the decomposition goes to completion.

Reaction stoichiometry

In first place, the balanced reaction is:

2 SO₃ → 2 SO₂ + O₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

SO₃: 2 molesSO₂: 2 moles O₂: 1 mole

The molar mass of the compounds is:

SO₃: 80.1 g/moleSO₂: 64.1 g/mole O₂: 32 g/mole

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

SO₃: 2 moles ×80.1 g/mole= 160.2 gramsSO₂: 2 moles ×64.1 g/mole= 128.2 grams O₂: 1 mole ×32 g/mole= 32 grams

Mass of oxygen produced

The following rule of three can be applied: if by reaction stoichiometry 160.2 grams of SO₃ form 32 grams of O₂, 240 grams of SO₃ form how much mass of O₂?

[tex]mass of O_{2} =\frac{240 grams of SO_{3}x 32 grams of O_{2} }{160.2grams of SO_{3}}[/tex]

mass of O₂= 47.94 grams

Given a 240.0 g sample of sulfur trioxide, 47.95 grams of oxygen are produced, assuming the decomposition goes to completion.

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HELP ASAP!!! please chemistry sucks

Answers

I believe it’s 146.06 g/mol

hope this helps! ^^
By adding all of the elements by their amount, the molar mass comes out to be 146. G/mol

Helppp 88.0 grams of Boron, how many atoms of Boron (B) are present?

Answers

Answer:

There are no atoms becuase atoms are not in elements.

Explanation:

what are the roles of the mucous select two options PLEASE HELP​

Answers

Answer:

The answer is A and C

When solid materials are heated.the heat absorbed/added to the materials caused the materials to change its form

Answers

Complete question is;

When solid materials are heated.the heat absorbed/added to the materials caused the materials to change its form from?

Answer:

From solid to liquid

Explanation:

When we heat solid materials, the heat causes the forces of attraction between the molecules to become weaker and as such, the material becomes more loose than it was in the solid state. As a result, the material now becomes a liquid because the molecules now have lesser forces of attraction and are a bit loose.

Identify the products in the reaction HCI + NaOH → NaCl + H20.
A. HCI, NaOH, NaCl, and H2O
B. HCl and NaOH
C. NaCl and H20
D. NaOH and H20

Answers

C the products are on the right side of the arrow

The products in the reaction HCI + NaOH → NaCl + H20, are C. NaCl and H20.

How are these the products ?

The reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) is a neutralization reaction, which means that it produces a salt and water. In this case, the salt is sodium chloride (NaCl) and the water is H2O.

The other options are not correct because they do not include all of the products of the reaction. Option (A) includes HCl and NaOH, but it does not include H2O. Option (B) only includes HCl and NaOH. Option (D) only includes NaOH and H2O.

In conclusion, option C is correct.

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Anna notices that different types of clothing stick together when they are dried in an electric dryer. When the clothes are pulled apart, they make sparks and a crackling sound due to electric forces of attraction. How can Anna reduce the amount the clothing clings together in the dryer?

Add a substance to the wash that reduces the number of charges transferred.
Increase the temperature of the air in the dryer to weaken the electric forces.
Dry more clothes at the same time so that there is less room for electric forces.
Change the charges on the clothes by running the dryer at a faster speed.

Answers

Answer:

A: Add a substance to the wash that reduces the number of charges transferred.

Explanation:

The attraction between opposite charges make the clothes attract together. To reduce them Increase the temperature of the air in the dryer to weaken the electric forces. Hence, option A is correct.

What is electric dryer?

An electric dryer is used to dry the clothes and hair or other substances using electric current. A substance can have both negative and positive charges. The opposite charges will attract together while the negative charges repel.

By exposing clothes to electric dryer it will gain electrons from the dryer and the positive poles of the clothes will attracts it. The electric current from the dryer will make clothes temporarily polarised.

If temperature increases, the intermolecular force of attraction decreases by making the kinetic energy of molecules raised. Therefore by increasing the temperature of air from the dryer the attraction can be reduced.

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Magnesium bromide is prepared in a laboratory using the reaction below. Typically, the magnesium bromide is recoveted as a solid by heating way the remaining water
Mg(s) + 2 HB-(aq) - MgBrac) + H200)
If 0.940 mole of HBr in solution is added to 16.5 grams of Mgo in a beaker and then is heated until dry, what are the expected contents of the beaker?

Answers

Can you give more examples?

You can increase a step-up transformer's voltage with


A. a power source connected to the primary coil

B. a source connected to the secondary coil.

C. increasing the number of loops in the primary coil.

D. increasing the number of loops in the secondary coil​

Answers

Answer:

A. a power source connected to the primary coil

Explanation:

How could the strength of an electromagnet be increased?

by reducing the length of the core (nail) of the electromagnet

by using the rubber material as the core for the electromagnet

by decreasing the amount batteries used for the electromagnet

by increasing the number of coils in the wires of the electromagnet.

Answers

I had this question on a test in K12

The answer is By increasing the number of coils in the wires of the electromagnet.

increasing coil wires is correct, like the other person answered.

with 24.1 moles of P4O10 how many moles of H3PO4 could be made

Answers

about 4.5 moles could be made p4

Calculate the mass (in g) of solute needed to prepare a solution with the given concentration and volume.
Sea water has a concentration of approximately 0.60 M sodium chloride. How much
sodium chloride is dissolved in 1.00 L of solution?
Coke has a concentration of 0.342 M. What mass of sugar (in g) is dissolved in a 2-L
bottle of coke?
What volume of concentrated nitric acid (15.8 M) is needed to prepare 4.0 L of a 2.0 M solution?
What volume of 9.0 M copper (II) sulfate stock solution is needed to prepare 3.0 L of a 5.0 M
solution?

Answers

Answer:

1. 35g NaCl.

2. 234g sugar.

3. 0.506L of concentrated nitric acid are needed.

4. 1.67L of 9.0M copper (II) sulfate are needed

Explanation:

Molarity is defined as the ratio between moles of solute and the volume of the solution.

1. 1.00L * (0.60mol / L) = 0.60 moles NaCl are dissolved

To convert moles to mass we must use its molar mass:

0.60mol NaCl * (58.44g/mol) =

35g NaCl

2. 2L * (0.342mol / L) = 0.684 moles Sugar = moles sucrose

0.684 mol * (342.30g / mol) = 234g sugar

3. 4L of a 2.0M are:

4L * (2.0mol/L) = 8moles

8mol * (1L / 15.8mol) = 0.506L of concentrated nitric acid are needed

4. 3.0L  * (5.0 mol / L) = 15.0 moles copper (II) sulfate.

15.0mol * (1L / 9.0mol) = 1.67L of 9.0M copper (II) sulfate are needed

12 G of carbon react with 16 G of oxygen how much carbon monoxide is formed ​

Answers

Answer:

28 g CO

Explanation:

First convert grams to moles.

1 mole C = 12.011 g (I'm just going to round to 12 for the sake of this problem)

12 g C • [tex]\frac{1 mol C}{12 g C}[/tex] = 1 mol C

1 mol O = 15.996 g (I'm just going to round to 16)

16 g O • [tex]\frac{1 mol O}{16 g O}[/tex] = 1 mol O

So the unbalanced equation is:

[tex]C + O_{2}[/tex] -> [tex]CO[/tex] (the oxygen has a 2 subscript because it is part of HONClBrIF meaning when not in a compound these elements appear in pairs - called diatomic elements)

The balanced equation is:

[tex]2 C + O_2[/tex] -> [tex]2 CO[/tex]

However, carbon is the limiting reactant in this equation and two moles cannot react because only 12 g (1 mole) are present. Therefore, use the equation

[tex]C + \frac{1}{2} O_2[/tex] -> [tex]CO[/tex].

1 mole of CO is formed, therefore 12 g + 16 g = 28 g CO.

The students in Mrs. Jamison's class were conducting a lab experiment to determine the if temperature affected how fast 2 drops of food coloring mixed into water. They used frozen water, refrigerated water, room temperature water, and hot water. Which water allowed the food coloring to mix the fastest?
A) Hot water
B) Frozen water
C) Refrigerated water
D) Room temperature water

Answers

Hot water because the particles are moving around much more faster increasing the possibility of them to bounce around and making it easier to mix

Answer:

A

Explanation:

True or false.

“Sleeping does not give us energy, but is important because it helps us repair wounds; think better, grow and survive.”

hurry pls pls plsss

Answers

Answer:

False

Explanation:

Isotope what dose it mean

Answers

Answer:

each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.

"some elements have only one stable isotope"

Explanation:

A metal crystallizes in the face‑centered cubic (FCC) lattice. The density of the metal is 12020 kg/m3, and the length of a unit cell edge, , is 389.08 pm. Calculate the mass of one metal atom in grams.

Answers

Answer:

  1.7700×10^-22 g

Explanation:

A face-centered-cubic cell contains 4 atoms, so the volume per atom is ...

  (389.80×10^-12 m)³/(4 atoms) ≈ 1.4725×10^-29 m³

Then the mass of 1 atom is ...

  (12020 kg/m³)(1.4725×10^-29 m³) ≈ 1.76995×10^-25 kg

  ≈ 1.7700×10^-22 g

_____

Additional comment

That is the approximate mass of a Palladium atom.

Answer:

1.7700×10^-22 g

Explanation:

2. What is the molarity of a CuBr2 solution that contains 446 g of solute in 5000 mL of solution?

Answers

Answer:

0.4 M

Explanation:

M=moles/Liters

Convert grams to moles (446/223.37=1.99668711)

Convert 5000 mL to liters (5000/1000)

Plug in the values and solve

M=2/5

M=0.4

PLEASE CAN SOMEONE EXPLAIN this FOR ME WHAT IS RADIOACTIVE ISOTOPES AND ANSWER THIS QUETION? A nitrogen atom has 7 protons and most common isotopes of nitrogen has 7 neutrons. A radioactive isotopes of nitrogen has 8 neutrons write the atomic number and mass number of this radioactive nitrogen as a chemical symbol with a subscript and superscript.​

Answers

Answer:

[tex]\frac{15}{7}N[/tex]

Explanation:

We already know that the mass number of an atom is the sum of the number of protons and the number of neutrons.

So, the mass number of this isotope is;

Number of protons = 7

Number of neutrons = 8

Mass number = 7 + 8 = 15

Hence, the isotope is;

[tex]\frac{15}{7}N[/tex]

If a cell were compared to a school, which part of the school would represent the cell's nucleus?
ОА the classroom walls because they give the structure to the school
B
the cafeteria cooks because they make food for the entire school
С
the principal because he or she controls all the activity in the school
D
the fence because it controls what enters and exits the school

Answers

Answer:

C-The principal because he or she controls all the activity in the school

Which characteristic is true of sexual reproduction but not of asexual reproduction?

Answers

Answer:

Sexual Reproduction involves two different parties

Explanation:

Asexual is the opposite, so it uses no one else to reproduce

Answer:

Sexual reproduction produces diverse offspring .

Sexual reprodction produces more variations whereas asexual reproduction usually produces very similar organisms

Explanation:

Which of the following do/does not change with the change in temperature?

i. Mole fraction.

ii. Molality.

Select one:
a. only i
b. Only ii
c. Both i & ii
d. Neither of them
(I did D and it was incorrect)

Answers

Answer:

c. Both i & ii

Explanation:

Moles do not change with temperature hence Mole fraction does not depends of temperature.

Molality is number of moles of solutes per kilogram of solvent. It has no relationship with temperature.

This means both of them do not change wit the change in temperature.

Correct option;

c. Both i & ii

Our bodies use nitrogen

Question 2 options:

directly from the air


after bacteria make N into ammonia molecules


from the plants and other animals we eat


all of the above

Answers

it's the 1 and 3 I think it's that hopefully it's right

A 150 g sample of brass at 90.0 degrees Celsius is placed in a calorimeter cup that contains 230 g of water at 20.0 degrees Celsius. Disregard the absorption of heat by the cup and calculate the final temperature of the brass and water. Specific heat of water = 4.18 J/gC, specific heat of brass=0.380 J/gC.

Answers

Answer:

for brass

mass m1 =150g

t1=90°c

specific heat of brass s1=0.380 J/gC.

for water

t2=20°c

mass m2=230g

Specific heat of water s2= 4.18 J/gC,

Explanation:

we have

Q1=Q2

m1s1{t-t1)=m2s2(t2-t)

150×0.380(t-90)=230×4.18(20-t)

57t-5130=961.4×20-961.4t

57t +961.4t=19228+5130

1018.4t=24358

t=24358/1018.4=23.91=24°c is final temperature

What is the highest occupied energy level for an atom of copper (Cu)? *

Answers

Answer:

third energy level - 18

hope this helps

Write 5 household products that have hazard symbol/symbols on them.

Answers

Answer:

A variety of household products are hazardous. Motor oil, pesticides, oil-based paints, mothballs, flea collars, weed killers, and some household cleaners

what is 20+9-10+67=?

Answers

Answer:

86

Explanation:

20 plus 9 equals 29 minus 10 equals 19 plus 67 equals 86

Answer:

86

Explanation:

20+9=29

29-10=19

19+67=86

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