The number to the right of an element's symbol (ex. c-12) identifies the of an isotope. a. atomic mass b. mass number c. atomic mass unit d. average atomic mass

Option (A) is the correct answer.

Explanation:

Atomic mass is defined as the summation of total number of protons and neutrons present in an element.

For example, in the number 12 represents the total number of protons and neutrons present in it.

As it is known that an atom of carbon always contains 6 protons but it can hold different number of neutrons.

Hence, in the number 12 represents the atomic mass.

Therefore, we can conclude that the number to the right of an element's symbol (ex. C-12) identifies the atomic mass.

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

→

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-