Question

The atom of an element a'made up of 4 protone, 5 neutrons and 4 electrons and
element B'made up of 15 protone, 16 neutron and 15 electrons, then write the
atomic number and mass number of elements, A and B

Answer 1

Answer:

For element A

Atomic number = Number of protons

so atomic no = 4

Mass number = Sum of neutrons and protons = 5+4 = 9

For element B

Atomic numner = 15

Mass number = 15+16= 31