Answer
See the explanation
Work Step by Step
a. The element has one electron in the second energy level
Second energy level includes the 2s and 2p orbitals.
One electron in this level means only 1 electron in 2s.
Element: Lithium (Li)
Configuration: 1s² 2s¹
Period: 2
b. There are two electrons in the 2s orbital
Full 2s orbital = 2 electrons.
Element: Beryllium (Be)
Configuration: 1s² 2s²
Period: 2
c. The electronic configuration is 1s² 2s² 2p⁵
Total electrons: 2 + 2 + 5 = 9
Element: Fluorine (F)
Atomic number: 9
Period: 2
d. The element contains six electrons in the second energy level
Second level: 2s² + 2p⁴ = 6 electrons
Element: Oxygen (O)
Configuration: 1s² 2s² 2p⁴
Period: 2
