Question

Periodic first 20 elements with atomic number, atomic mass , valency, symbol with electronic configuration

Answer 1

Lithium is a reactive silver metal.

Atomic Number: 3

Symbol: Li

Atomic Mass: 6.94 (6.938–6.997)

Electron Configuration: [He] 2s1

Group: group 1, s-block, alkali metalBeryllium is a shiny gray-white metal.

Atomic Number: 4

Symbol: Be

Atomic Mass: 9.0121831(5)

Electron Configuration: [He] 2s2

Group: group 2, s-block, alkaline earth metalBoron is a gray solid with a metallic luster.

Atomic Number: 5

Symbol: B

Atomic Mass: 10.81 (10.806–10.821)

Electron Configuration: [He] 2s2 2p1

Group: group 13, p-block, metalloid