Chapter 4-Structure of the Atom

______ is the number of protons in an atom

atomic number

______ is the sum of number of protons and neutrons in an atom

mass number

_______ has same atomic number but different mass number

isotope

_______ has same mass number but different atomic number

isobar

_______ particles were used in Rutherford’s experiment

alpha

_______ makes up the mass of an atom

nucleus

the number of protons and electrons in an atom are always ______

equal

_______ has the same mass as protons

neutron

neutral subatomic particle is _______

neutron

Cathode ray are a beam of fast moving ______ .

electrons

The penetrating power of B-rays is_______ times more than a-rays.

100

The control rods in a nuclear reactor are made up of _________.

Cadmium

____________ are stored in deep mines which are not in use.

radioactive materials

The K-shell of any atom cannot have more than _________ electrons.

two

Mass of an electron is 1/1837 times less than the mass of one atom of__________.

hydrogen

An atom is the smallest unit of an element which takes part in a _________.

chemical reaction