(1)Write electronic configuration of element X which has atomic number = 15.Write its valency also.
(3) Differentiate between atomic number and mass number.
(4) An element has mass number equal to 32. What do you understand by it?
(5)If number of electron in outermost shell of an atom is 6. What will be the charge of atom?
(6) Complete the table given below –
|SN||Atomic number||Number of proton||Number of neutron||Mass number||Distribution of electrons||Valency|
(8) Differentiate between average atomic mass and mass number.
(10) Who proposed that electrons are embedded in positive sphere-
(i) J.J.Thomson (ii) Rutherford’s Model (iii) Bohr’s Model