Why does Helium have zero valency?

Write the complete symbol for the atom with the given atomic number [Z] & mass number [A].

How are the isotopes of hydrogen represented?

An atom contains 3 protons, 3 electrons and 4 neutrons. What is its atomic number, mass number & valency?

From the symbol ³²₁₆S, state: i) Atomic number of sulphur ii) Mass number of sulphur iii) Electronic configuration of sulphur

Give the symbol, relative charge & mass of the three subatomic particles.

State the maximum capacity of various shells to accommodate electrons.

How many electrons are present in the valence shell of nitrogen & argon?

Which kind of elements have tendency to lose electrons? Give example.

What are valence electrons? Give example.

Give one achievement and one limitation of J.J. Thomson's model of atom.

Identify the isotopes out of A, B, C & D: ³³A₁₇, ⁴⁰B₂₀, ³⁷C₁₇, ³⁹D₁₉

Write the charges on subatomic particles.

Define the following terms: a) Atomic number b) Mass number

Name the particles which determine the mass of an atom.

What are isobars?

Give the number of protons in ³⁵Cl₁₇.

What type of charge is present on the nucleus of an atom?

How many electrons at the maximum can be present in the first shell?

What was the model of an atom proposed by Thomson?

How many times is a proton heavier than an electron?

Which is heavier, neutron or proton?

Name the scientist and his experiment which proved that the nucleus of an atom is positively charged.