Atomic structure

Matter is built up of

• Solid liquid gas

• Atoms, Molecules , Radicals

• Plastic

• Small particles

A molecule of an element is

• Water

• Chlorine

• Ammonia

Who done the discovery of "electrons"

• J.J Thomas

• Rutherford

Radicals are of how many types

In Periodic Table eighteen vertical columns are called

• Group

• Periods

Helium symbol

• He

• H

• Hi

Sodium symbol

• S

• Si

• Na

• Ne

• So

Oxygen atomic number

• 5

• 8

• 7

• 12

• 28

Valency of boron

• ±1

• +1

• 1-

• —_1

What is a subatomic particle with a positive charge that is in the nucleus of an atom?

• neutron

• proton

• electron

• valence electron