atomic number and atomic mass

The total number of protons and neutrons present in one atom of an element is known as its mass number. Mass number = number of protons + number of neutrons It can also be said that: Mass number = h..

Atomicity is the number of atoms of an element present in one molecule of that element. They can be monoatomic (He), diatomic (H 2 ), triatomic (O 3 ) and polyatomic (S 8 ..

Experiments have determined that the mass of an atom is very small, ranging from 1.7x10 -24 g to about 4.0x10 -22 g. It is very difficult to accurately weigh a bunch of atoms, as they are extremely light, small, and invisible; they weigh too little for us to express th..

Atomic masses of many elements are in fractions not in whole numbers..

The nuclei of atoms are made up of protons and neutrons. These two components of the nucleus are referred to as nucleon..

Atoms and Molecules - Summary The law of conservation of mass states that the masses of the reactants and products remain unchanged. The law of constant proportions states that all pure specimens of a compound always contain the same elements combined together in the s..

>The mass of electrons is negligible compared to the mass of the protons. Ordinary hydrogen is the only element that has no neutron in it. According to Bohr electrons revolve around the nucleus in fixed orbits called K, L, M, N etc. The energy of the shells increases as the dist..

Atomic Nucleus - It is the central core of the atom where the entire +ve charge and mass is concentrated. It is a tiny sphere of diameter ranging from 10 - 1 5 m to 10 - 1 4 m. A nucleus is made up of particles called neutrons and protons. A neutron does not carry any ..

. In it, he pictured a sphere of positive charges mixed together with an equal number of electrons. For his theoretical and experimental investigations into the electron and the conduction of electricity by gases he was awarded the 1906 Noble prize in Physics. He and his student Rutherfor..

Atomic Mass Unit Scale - The scale in which the relative atomic masses of different atoms are expressed is called atomic mass unit sca..