Question

Lithium (Li) and oxygen (O) are both in period 2. They both have _____.

Answer 1

They both have two electron shells

Further explanation

The period 2 element lies in the second row of the periodic system.

Consists of the elements: lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon

• Lithium (Li)

atomic number : 3

electron configuration : [He] 2s¹

atomic number = number of proton=number of electron(in neutral atom)

So Li have 3 protons and 3 electrons

Because it fills the 2s orbital it has 2 shells

• Oxygen (O)

atomic number : 8

electron configuration :  [He] 2s²2p⁴

So O have 8 protons and 8 electrons

Because it fills the 2s and 2p orbital it has 2 shells

So Lithium (Li) and Oxygen (O) are both have two electron shells