When a radioactive isotope releases a beta particle the atomic number of the new element is

The atomic number of the new element increases by 1 unit.

Explanation:  

Beta-decay: In this process, a neutron gets converted into a proton and an electron releasing a beta-particle. The beta particle released is basically a electron with -1 charge and no mass.

General representation of an element is given as:

where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

i think it's c. i'm not sure but i think so.

no, the red giant is the hottest with 2.00.000.000 degrees celsius. while the white dwarf only 25,000 degrees celsius.