Unit 1.8

Question 1

What are valence electrons?

Answer 1

The electrons that are in the outermost electron shell

Question 2

What are valence shells?

Answer 2

The shell that combines electrons furtherest from the nucleus

Question 3

1st Electron Shell

Answer 3

2 Electrons

Question 4

2nd Electron Shell

Answer 4

8 Electrons

Question 5

3rd Electron Shell

Answer 5

8 Electrons

Question 6

4th Electron Shell

Answer 6

18 Electrons

Question 7

5th Electron Shell

Answer 7

18 Electrons

Question 8

6th Electron Shell

Answer 8

32 Electrons

Question 9

7th Electron Shell

Answer 9

32 Electrons

Question 10

Why are noble gasses stable?

Answer 10

They are usually un-reactive because they have a full valence shell(farthest to the right)

Question 11

What two types of elements combine in ionic bonding?

Answer 11

Non-metals and metals

Question 12

What happens to metals in an ionic bond?

Answer 12

Lose electrons and become + charged

Question 13

What happens to non-metals in an ionic bond?

Answer 13

Gain electrons and become - charged

Question 14

What is covalent bonding?

Answer 14

Happens when 2 or more non-metals elements combine by sharing electrons

Question 15

1. Which of the following isotopes has 30 neutrons?
   (A) Manganese-55
   (B) Nitrogen-15
   (C) Phosphorus-30
   (D) Zinc-65

Answer 15

Answer: All of these isotopes are written with their mass number. The mass number is the number of protons plus neutrons. Manganese has 25 protons; therefore, 55-25 = 30 neutrons.

Question 16

2 .The ionization energy and atomic radius for aluminum is 578kJ/mol and 143 pm, respectively. What is the most likely ionization energy and atomic radius for silicon?
(A) 496 kJ/mol and 110 pm
(B) 496 kJ/mol and 180 pm
(C) 789 kJ/mol and 110 pm
(D) 789 kJ/mol and 180 pm

Answer 16

Answer: When comparing elements in the same row, one must look at the number of protons the element has. Since silicon has more protons in its nucleus, it is better at attracting its electrons than aluminum is. This makes the first ionization energy greater and the radius smaller.

Question 17

3. What is the electron configuration for Fe^2+?
   (A) 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6
   (B) 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^4
   (C) 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^6
   (D) 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8

Answer 17

Answer: When electrons are removed from atoms, they are removed from the valence shell, which for iron is the fourth energy level. The valence electrons are the electrons in the highest energy level. Therefore, the electron configuration of Fe^2+ is 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6.

Question 18

4. Given the following information, a 1.00 g sample of which of the following substances contains the greatest amount of chlorine?
   (A) Li Cl
   (B) K Cl
   (C) Na Cl
   (D) Rb Cl

Answer 18

Answer: The percent composition of chlorine in LiCl is greatest, therefore, in samples of the same mass, the mass of chlorine will be greatest in the sample with the greatest mass percent.

Question 19

5. Which of the following correctly identifies which has the greater first ionization energy, Na or Mg, and supplies the best reason?
   (A) Mg, because of its greater nuclear charge.
   (B) Mg, because it has a full sub-shell of electrons.
   (C) Na, because it has a greater electronegativity
   (D) Na, because of its greater mass.

Answer 19

Answer: When comparing two elements in the same period, one must consider the nuclear charge. The nuclear charge refers to the number of protons, of which magnesium contains more. with more protons, Mg has a greater force of attraction on its electrons.