EVERYDAY SCIENCE

Detailed explanation-1: -The total weight of an atom is called the atomic weight. It is approximately equal to the number of protons and neutrons, with a little extra added by the electrons. The stability of the nucleus, and hence the atom’s radioactivity, is heavily dependent upon the number of neutrons it contains.

Detailed explanation-2: -Proton and Neutron have approximately the same mass, about 1.67 × 10-24 grams, or one atomic mass unit (AMU) or one Dalton.

Detailed explanation-3: -The mass number of an atom is equal to the number of protons plus the number of neutrons that it contains. In other words, the number of neutrons in any atom is its mass number minus its atomic number. Although all atoms of a given element must have the same atomic number, they need not all have the same mass number.

Detailed explanation-4: -Mass number = Number of protons + Number of neutrons One atom of sodium, for example, contains 12 neutrons and 11 protons, therefore the mass number of sodium is 11+12=23. Similarly, because a carbon atom contains 6 protons and 6 neutrons, its mass number is 6+6=12.

Detailed explanation-5: -Protons and neutrons have approximately the same mass, but they are both much more massive than electrons (approximately 2, 000 times as massive as an electron). The positive charge on a proton is equal in magnitude to the negative charge on an electron.