`(a)` `text(Atomic Number) (Z)` : The atomic number of an element is the number of protons contained in the nucleus of the atom of that element.
`(b)` `text(Nucleons)` : Protons and neutrons are present in a nucleus. So, these fundamental particles are collectively known as nucleons.
`(c)` `text(Mass Number) (A)` : The total number of protons and neutrons i.e. the number of nucleons present in the nucleus is called the mass number of the element.
`(d)` `text(Nuclide)` : Various species of atoms in general. A nuclide has specific value of atomic number and mass number.
`(e)` `text(Isotopes)` : Atoms of the element with same atomic number but different mass number e.g. `text()_1H^1, text()_1H^2, text()_1H^3`. There are three isotopes of hydrogen.
`(f)` `text(Isobars)` : Atoms having the same mass number but different atomic numbers, e.g. `text()_(15)P^(32)` and `text()_(16)S^(32)` are called isobars.
`(g)` `text(lsotones)` : Atoms having the same number of neutrons but different number of protons or mass number, e.g. `text()_6C^(14), text()_8O^(16), text()_7N^(15)` are called isotones.
`(h)` `text(lsolectronic)` : Atoms, molecules or ions having same number of electrons are isoelectronic e.g. `N_2`, `CO`, `CN^(-)`.
(i) `text(lsosters)` : Molecules having same number of atoms and also same number of electrons are called isosters.
e.g., (i) `N_2` and `CO` ii) `CO_2` and `N_2O` iii) `HCl` and `F_2`
(j) `text(Atomic mass unit)` : Exactly equal to (`1//12`) of the mass of `text()_6C^(12)` atom
`1` amu `= 1.66 xx 10^(-27)` kg. If it is converted to energy then `E = 931.5 MeV`
`(k)` `text(lsodiapheres)` : Atoms having same difference between neutrons & protons are called isodiapheres. They have same value of `N-Z` or `A - 2Z`.
Example : i) `text( )_(92)^(238)U` & `text()_(92)^(234)Th` ii) `text()_1H^(2)` & `text()_3^7(Li)`
`(a)` `text(Atomic Number) (Z)` : The atomic number of an element is the number of protons contained in the nucleus of the atom of that element.
`(b)` `text(Nucleons)` : Protons and neutrons are present in a nucleus. So, these fundamental particles are collectively known as nucleons.
`(c)` `text(Mass Number) (A)` : The total number of protons and neutrons i.e. the number of nucleons present in the nucleus is called the mass number of the element.
`(d)` `text(Nuclide)` : Various species of atoms in general. A nuclide has specific value of atomic number and mass number.
`(e)` `text(Isotopes)` : Atoms of the element with same atomic number but different mass number e.g. `text()_1H^1, text()_1H^2, text()_1H^3`. There are three isotopes of hydrogen.
`(f)` `text(Isobars)` : Atoms having the same mass number but different atomic numbers, e.g. `text()_(15)P^(32)` and `text()_(16)S^(32)` are called isobars.
`(g)` `text(lsotones)` : Atoms having the same number of neutrons but different number of protons or mass number, e.g. `text()_6C^(14), text()_8O^(16), text()_7N^(15)` are called isotones.
`(h)` `text(lsolectronic)` : Atoms, molecules or ions having same number of electrons are isoelectronic e.g. `N_2`, `CO`, `CN^(-)`.
(i) `text(lsosters)` : Molecules having same number of atoms and also same number of electrons are called isosters.
e.g., (i) `N_2` and `CO` ii) `CO_2` and `N_2O` iii) `HCl` and `F_2`
(j) `text(Atomic mass unit)` : Exactly equal to (`1//12`) of the mass of `text()_6C^(12)` atom
`1` amu `= 1.66 xx 10^(-27)` kg. If it is converted to energy then `E = 931.5 MeV`
`(k)` `text(lsodiapheres)` : Atoms having same difference between neutrons & protons are called isodiapheres. They have same value of `N-Z` or `A - 2Z`.
Example : i) `text( )_(92)^(238)U` & `text()_(92)^(234)Th` ii) `text()_1H^(2)` & `text()_3^7(Li)`