$$Z = \text{Valence Electrons} + \text{Inner Core Electrons}$$

Question 1

Which of the following best describes valence electrons in a main group element?

Accepted Answer

Electrons involved in forming chemical bonds, equal to the group number for main group elements.

Question 2

A chlorine atom has an atomic number $$Z = 17. $$How many valence electrons does it have?

Accepted Answer

$$7$$

Question 3

How many inner core electrons does a silicon atom possess?

Accepted Answer

$$10$$

Question 4

If a carbon atom has $$6$$ total electrons, how many of these are valence electrons?

Accepted Answer

$$4$$

Question 5

Which equation correctly relates the total number of electrons ($$Z$$), valence electrons, and inner core electrons for a main group element?

Accepted Answer

$$Z = 	ext{Valence Electrons} + 	ext{Inner Core Electrons}$$

Question 6

A nitrogen atom has $$7$$ total electrons. How many are valence electrons and how many are inner core electrons?

Accepted Answer

$$5$$ valence electrons, $$2$$ inner core electrons

Question 7

Which of the following statements is TRUE about inner core electrons?

Accepted Answer

They are the electrons not involved in chemical bonding.

Question 8

For an element in Group 2A, what is the number of valence electrons?

Accepted Answer

$$2$$

Question 9

If an atom has $$12$$ total electrons and belongs to Group 2A, how many inner core electrons does it have?

Accepted Answer

$$10$$

Question 10

Which of the following is the correct electron arrangement for a chlorine atom ($$Z = 17$$)?

Accepted Answer

2 electrons in the first shell, 8 in the second, 7 in the third

Question 11

Which group number corresponds to the number of valence electrons for main group elements?

Accepted Answer

Group number

Question 12

A student claims that all electrons in an atom are valence electrons. Which statement best refutes this claim?

Accepted Answer

Only electrons in the outermost shell are valence electrons; the rest are inner core electrons.

Question 13

If an atom has $$8$$ total electrons and $$6$$ inner core electrons, how many valence electrons does it have?

Accepted Answer

$$2$$

Question 14

Which of the following elements has $$5$$ valence electrons?

Accepted Answer

Nitrogen ($$Z = 7)$$

Question 15

A main group element has $$15$$ total electrons and $$5$$ valence electrons. What is its group number?

Accepted Answer

Group 5A

Question 16

Which of the following is NOT a property of valence electrons?

Accepted Answer

They are always equal to the atomic number.

Question 17

A main group element has $$18$$ total electrons and $$8$$ valence electrons. How many inner core electrons does it have?

Accepted Answer

$$10$$

Question 18

Which of the following best explains why inner core electrons do not participate in chemical bonding?

Accepted Answer

They are shielded by the valence electrons and are held tightly by the nucleus.

Question 19

If an atom has $$20$$ total electrons and belongs to Group 2A, what is the number of inner core electrons?

Accepted Answer

$$18$$

Question 20

Which of the following elements has $$2$$ valence electrons and $$10$$ inner core electrons?

Accepted Answer

Magnesium ($$Z = 12)$$

Main Group Elements: Valence and Core Electrons

Study Guide - Practice Questions