CA_Lesson_2_Classification_of_the_Elements

Question 1

Why do elements in the same group have similar properties?

Answer 1

Because they have the same number of valence electrons.

Valence electrons determine how elements react chemically.

Question 2

What is a valence electron?

Answer 2

An electron in an atom’s outermost orbital; determines the chemical properties of an atom.

Valence electrons are crucial for bonding and reactivity.

Question 3

What determines the chemical properties of an element?

Answer 3

Electron configuration.

Electron configuration influences how atoms interact and bond with each other.

Question 4

How many valence electrons do all group 1 elements have?

Answer 4

One valence electron.

Question 5

What is the electron configuration of hydrogen?

Answer 5

1s^1.

Question 6

What is the electron configuration of lithium?

Answer 6

[He]2s^1.

Question 7

What is the electron configuration of sodium?

Answer 7

[Ne]3s^1.

Question 8

What is the electron configuration of potassium?

Answer 8

[Ar]4s^1.

Question 9

How many valence electrons do group 2 elements have?

Answer 9

Two valence electrons.

Question 10

For elements in groups 13–18, how is the number of valence electrons determined?

Answer 10

It is ten less than their group number.

Question 11

What indicates the period on the periodic table in which an element is found?

Answer 11

The energy level of an element’s valence electrons.

Question 12

What is the electron configuration of helium?

Answer 12

1s^2.

Question 13

What is the electron configuration of neon?

Answer 13

[He]2s^2 2p^6.

Question 14

What is the electron configuration of argon?

Answer 14

[Ne]3s^2 3p^6.

Question 15

What is the electron configuration of krypton?

Answer 15

[Ar]4s^2 3d^{10} 4p^6.

Question 16

What are the four blocks of the periodic table?

Answer 16

s, p, d, and f.

Question 17

What do s-block elements consist of?

Answer 17

Groups 1 and 2, plus the element helium.

Question 18

How many electrons do Group 1 elements have in their s orbital?

Answer 18

One electron.

Question 19

How many electrons do Group 2 elements have in their s orbital?

Answer 19

Two electrons.

Question 20

What does the p-block consist of?

Answer 20

Groups 13–18, which fill the p orbitals.

Question 21

What is unique about Group 18 elements regarding their orbitals?

Answer 21

Both the s and p orbitals of the period’s principal energy level are completely filled.

Question 22

What is the d-block known for?

Answer 22

It contains the transition metals and is the largest block.

Question 23

What do f-block elements contain?

Answer 23

Filled or partially filled outermost s orbitals and filled or partially filled 4f and 5f orbitals.

Question 24

What can the number of valence electrons indicate for representative elements?

Answer 24

The group number.

Question 25

What does the number 5 in 5s^2 indicate for strontium?

Answer 25

That strontium is in period 5.

Question 26

Which block does strontium belong to?

Answer 26

s-block.

Question 27

What is the group number of strontium based on its electron configuration?

Answer 27

Group 2.

Question 28

In which block is group 17 on the periodic table?

Answer 28

The p-block.

Question 29

Which block on the periodic table has the most elements?

Answer 29

The d-block.

Question 30

For elements in groups 13-18, the number of valence electrons is ______.

Answer 30

ten less than their group number.