Why and how are elements arranged in 4 period

Answer:

Only Student A

Explanation:

The first thing to consider in the diagrams of student A and B is to be sure that that the diagrams obey the octet rule and represent the written formula of ammonia (NH3). Clearly, only the diagram drawn by student A satisfy the these conditions.

If we look at the both diagrams closely, we will discover that the diagram drawn by student B does not satisfy the octet rule nor the trivalency of nitrogen even though it shows the lone pair of electrons on nitrogen hence it can not be the correct dot electron structure for NH3.

Answer: It is neither A or B

Explanation: I took the test and got this correct. Many people are saying only B, but that is wrong.

( please give brainliest :) )

Explanation:

As you cool a matter to absolute zero, their kinetic energy reduces significantly and the molecules slows down and begins to aggregate together.

Answer:

0.92moles

Explanation:

Given reaction:

              2Fe + 3Cl₂ →  2FeCl₃

Mass of FeCl₃  = 100g

Unknown:

Number of moles of Cl₂  needed = ?

Solution:

To solve this problem, we work from the known specie to the unknown.

From the mass of the FeCl₃ given, we can solve for the number of moles of the unknown.

  Number of moles  = [tex]\frac{mass}{molar mass}[/tex]  

  Molar mass of  FeCl₃ = 56 + 3(35.5) = 162.5g/mol

   Number of moles  = [tex]\frac{100}{162.5}[/tex]  = 0.62mole

From the reaction expression;

           2 mole of FeCl₃ is produced from 3 moles of  Cl₂  

           0.62 mole of FeCl₃ will be produced from [tex]\frac{0.62 x 3}{2}[/tex]   = 0.92mole

The number of moles of Cl₂  = 0.92moles

Answer:

The reaction produces insoluble lead (II) sulphate which coats the surface of lead (II) nitrate  [Pb(NO3)]

Answer:

Sound.

Explanation:

Sound requires a medium such as air to travel.

Answer:

V₂ = 112.14 mL

Explanation:

Given data:

Initial volume = 500 mL

Initial pressure = 270 mmHg (270/760 =0.355 atm)

Initial temperature = 55 °C (55 +273 = 328 K)

Final temperature = 100°C (100+273 = 373 K)

Final volume = ?

Final pressure = 1.8 atm

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

V₂ = P₁V₁ T₂/ T₁ P₂  

V₂ = 0.355 atm × 500mL × 373 K / 328 K × 1.8 atm

V₂ = 66207.5 atm .mL. K /  590.4 K.atm

V₂ = 112.14 mL

Answer:

T₂ = 573.86 K

Explanation:

Given data:

Initial volume = 1.32 L

Initial temperature = 30.0°C (30+273 = 303 K)

Final volume = 2.50 L

Final temperature in car = ?

Solution:

Solution:

The given problem will be solve through the Charles Law.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume  

T₂ = Final temperature

Now we will put the values in formula.

V₁/T₁ = V₂/T₂

T₂ = V₂T₁/V₁

T₂ = 2.50 L × 303 K / 1.32 L

T₂ = 757.5 L.K / 1.32 L

T₂ = 573.86 K

Answer:

Gram

Centi-

Centimeter

Kilogram

Decimeter

Liter

Decimal System

Kilo-

Kilometer

Area

Answer:

b

Explanation:

i looked it up on Google

Answer:

Explanation:

before the reaction you have K=2 and Cl=4

after the reaction K=2 and Cl=2 so it does not follow the law of conservation

Answer:

d is the correct answer i think

Answer:

Explanation:

Firstly, it should be noted that melting and freezing points are the same. Thus, when a substance melts at a certain temperature, it means it can also start freezing/solidifying at that same temperature. That been said, when the substance P is a solid at a certain temperature, the other compound Q will boil at that same temperature and hence will be a gas at that same temperature.

If P is solid, it simply means that Q must still be in the liquid state.

From the question, we can see that, the melting point of P and the boiling point of Q are the same. The melting point of a substance is the temperature at which the solid turns to liquid while the boiling point of a substance is the temperature at which a liquid turns to a gas.

If P is solid, it simply means that Q must still be in the liquid state. It has not yet started boiling since the melting point of P and the boiling point of Q are the same.

Learn more: https://brainly.com/question/8553652

Explanation:

 We are to write the orbital notation and electronic configuration of sulfur and iron.

The orbital notation shows the filling of electrons into orbitals or sublevels.

Electron configuration  shows the distribution of electrons into shells;

        Number of electrons     Electron configuration     Orbital notation

S                  16                                   2 8 6                      1s² 2s² 2p⁶ 3s² 3p⁴

Fe                26                                2, 8, 14 2           1s² 2s² 2p⁶ 3s² 3p⁶3d⁶4s²        

Answer:

A.) It cannot be quickly replaced.

Explanation:

Aluminum is extremely useful to humans but is semi-difficult to produce. Because of this, your answer will be numero uno. (Or A.)

Answer: Due to the sharing of electrons, they exhibit characteristic physical properties that ... Here, we discuss two classes of compounds based on the bond type that ... Covalent bonds are characterized by the sharing of electrons between two or ... Describe the types of orbital overlap that occur in single, double, and triple bonds

Explanation: That's what I think it is.

Answer:

fewer collisions occur between particles or lowering the temperature

Explanation:

The chemical equation is said to be balanced if the number of atoms in the reactants and products is the same

Equation balanced ⇒ total number of atoms in reactants(on the left)= total number of atoms in products(on the right)

H₂+O₂---> H₂O

Reactants : H₂, O₂

Products : H₂O

not balanced

H₂O₂ ---> H₂O+O₂

Reactants : H₂O₂

Products : H₂O, O₂

not balanced

Na+O₂ ---> Na₂O

Reactants : Na, O₂

Products :  Na₂O

not balanced

N₂+H₂ ---> NH₃

Reactants : N₂, H₂

Products :  NH₃

not balanced

P₄+O₂---> P₄O₁₀

Reactants : P₄, O₂

Products :  P₄O₁₀

not balanced

Fe+H₂O ----> Fe₃O₄ + H₂

Reactants : Fe, H₂O

Products :  Fe₃O₄

not balanced

Answer:

A. Hot water increases the collision rate of the molecules, causing the

reaction to occur faster.

Explanation:

Hot water molecules move faster than cold water molecules.

Ionic compounds are formed from metal and non-metal elements

The chemical formula of compounds (especially ionic compounds) can be determined from the charge of each ion.

Determination of the ionic charge of the constituent elements of the compound can be seen from the electron configuration to achieve stability according to the octet rule

The charge of each ion will be crossed in the compound

Aluminum bromide

Al³⁺ + Br⁻ ⇒ AlBr₃

Magnesium bromide

Mg²⁺ + Br⁻ ⇒ MgBr₂

Sodium sulfide

Na⁺ + S²⁻ ⇒ Na₂S

Sodium nitride

Na⁺ + N³⁻ ⇒ Na₃N

Answer:

B - What we change

Explanation:

Dependent Variable - What we measure

Control Variable - what stays the same

Conclusion - what we conclude

Hope this can Help!

:D

1. ₉¹⁹F

2. Mg(OH)₂

3. 2H₂ + O₂ ⇒ 2H₂O

1. Fluorine, atomic number : 9 , mass number = 19

Symbol : ₉¹⁹F

protons=electrons=atomic number = 9

neutrons = mass number - atomic mass

[tex]\tt n=19-9=10[/tex]

Configuration : [He] 2s² 2p⁵

2. Magnesium hydroxide is an ionic compound and is a strong base consisting of 2 ions:

Positive ion: Magnesium: Mg²⁺

negative ion: Hydroxide: OH⁻

The charges of the two are crossed, so that the compound becomes:

Mg(OH)₂

3. Reaction :

H₂ + O₂ --------> H₂O

give coefficient :

aH₂ + bO₂ --------> H₂O

H, left = 2a, right 2⇒2a=2⇒a=1

O, left = 2b, right 1⇒2b=1⇒b=0.5

Reaction becomes :

H₂ + 0.5O₂ --------> H₂O x 2

2H₂ + O₂ --------> 2H₂O

Answer:

Ca3(PO4)2 and Na

Explanation:

The reaction equation is;

3Ca + 2Na3PO3 -------> Ca3(PO3)2 + 6Na

We must remember that calcium is above sodium in the electrochemical series. This implies that calcium can displace sodium from its solution. Calcium has a reduction potential of -2.87 V while sodium has a reduction potential of -2.71 V. The ion with the more negative reduction potential can easily displace the other in aqueous solution.

This explains why the reaction above is possible.

Answer:

[tex]\boxed {\boxed {\sf d\approx 1.84 \ g/mL}}[/tex]

Explanation:

Density can be calculated by dividing the mass by the volume.

[tex]d=\frac{m}{v}[/tex]

The mass of the sulfuric acid is 65.14 grams. The volume is 35.4 milliliters.

[tex]m= 65.14 \ g \\v= 35.4 \ mL[/tex]

Substitute the values into the formula.

[tex]d=\frac{65.14 \ g}{35.4 \ mL}[/tex]

Divide.

[tex]d=1.84011299 \ g/mL[/tex]

Let's round to the nearest hundredth to make the answer concise.

The 0 in the thousandth place tells us to leave the 4 in the hundredth place.

[tex]d\approx 1.84 \ g/mL[/tex]

The density of sulfuric acid is about 1.84 grams per milliliter.

Answer:

VI only

Explanation:

Answer:

6 hours

Explanation:

If it is traveling at 50mph and needs to reah 300 miles, to figure this problem out you would want to divide 300 by 50 to get 6 hours. So it will take six hours until the car travels 300 miles

Hope this helps.

Answer: A car travels at a rate of 50 miles per hour. how long will it take the car to travel 300 miles?

Explanation: .

Applying the distance formula:

d = rt

where

d is distance (300 miles)

r is rate (50 mph)

t is time (hours)

.

300 = 30t

300/30 = t

10 hours = t

Answer:

By Newton's laws. we know that when we apply a force in an object, then we also are applying acceleration, given by the equation F =ma, where F is the applied force, m is the mass of the object and a is the acceleration.

Now in this problem, we only have that James want to move objects from point A to point B. If the problem says that James does it at the same time for each object, then we could assume that each object has the same acceleration A.  

F = m*A

then if the mass of the o

object increases, the force needed to move it at the given acceleration will increase also, then the object that requires less force is the object with less mass, in this case, the toy car.

But in this problem never says that the objects are moved with the same acceleration (or in the same amount of time), then we could apply the same force in the four objects and eventually the four will get to the point b ( for example, the refrigerator would take a lot more of time than the toy car.

Answer:

it's c, the toy car.

Explanation:

Answer:

A change in the shape of a substance

Explanation:

Because when ths shape of a sunstance changes , its physical appearance changes .A physical change is a change to the physical—as opposed to chemical—properties of a substance. They are usually reversible. The physical properties of a substance include such characteristics as shape (volume and size), color, texture, flexibility, density, and mass.

Answer:

1.181 × 10²⁴ molecules CO₂

General Formulas and Concepts:

Chemistry - Atomic Structure

Explanation:

Step 1: Define

86.34 g CO₂

Step 2: Identify Conversion

Avogadro's Number

Molar Mass of C - 12.01 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of CO₂ - 12.01 + 2(16.00) = 44.01 g/mol

Step 3: Convert

[tex]86.34 \ g \ CO_2(\frac{1 \ mol \ CO_2}{44.01 \ g \ CO_2} )(\frac{6.022 \cdot 10^{23} \ molecules \ CO_2}{1 \ mol \ CO_2} )[/tex] = 1.18141 × 10²⁴ molecules CO₂

Step 4: Check

We are given 4 sig figs. Follow sig fig rules and round.

1.18141 × 10²⁴ molecules CO₂ ≈ 1.181 × 10²⁴ molecules CO₂

Answer:

Explanation:

by stoichiometry

nNH3/2=nH2/3

0.25/2=nH2/3

nH2=0.25×3/2

nH2=0.375 mol

so its 0.38 mol

Answer:

I have this quiz rn I will try 0.38 if it is right I’ll edit this and say that

Explanation: