Atomic Structure

Who is credited with discovery of electron ?

• Rutherford

• Goldstein

• J.J.Thomson

• James chadwick

An element has an electronic configuration of 2, 8, 7. Its valency is

• 2

• 7

• 3

• 1

______is not capable of independent existence.

oxygen is a

• Molecule

• Atom

Number of protons in the nucleus is called______

• Mass number

• electric charge

• periodic number

• Atomic number

During a chemical reaction, atomic number

• Changes

• Changes and then is restored

• Changes alternately

• Remains same

When atoms of different elements combine, they form...?

• Molecules

• Compounds

• Mixtures

• Elements

If atom loses electron, they becomes positively charged.

• True

• False

Carbon has a mass number of 12. thus, it has_______ protons and _______ neutrons.

Water (H2O) is an example of a..

• Molecule

• Compound

• Element

• Atom