Some basic concept of chemistry|chemistry 1| short notes for NEET 2024-25| Summary notes for NEET 2024-25| As per updated syllabus

SOME BASIC CONCEPTS
CHEMISTRY

1. ATOMICITY: No of atoms in a molecu
Multiply by atomicity
MOLECULES A
Divide by atomicity
ATOMS MOLECULES
Molecules are of two types-
 Homoatomic- S8, P4
 Heteroatomic- H2O, SO2

2. SUBATOMIC PARTICLES:
Particles Charge Relative charge Mass
 Electron -1.6×10-19 C -1 9.1×10-31 k
 Proton 1.6×10-19 C +1 1.673×10-
 Neutron neutral 0 1.675×10
NOTE: 1) Mass of electron = 1÷1837 (mass of proton or ma
neutron.
2) Mass of proton ≈ mass of neutron = 1 amu or 1u.

, A = Atomic mass or mass number, Z = Atomic number, X =
 Atomic number (Z): Number of protons present in a
 Mass number (A): Number of nucleons i.e. protons +
present in an atom.
 In an atom, number of protons = Z, number of neutr
 Atomic number, mass number, number of electrons
and neutrons are always whole number.
 Number of electrons in an atom-
ATOM

NEUTRAL/UNCHARGED/ISOLATED ATOM CHARGED AT
Number of electrons = number of protons = Z
CATIONS
 Cation Anion
Positively charged. Negatively c
Formed by loss of e. Formed by g
Number of e < p. Number of e
Number of e = number of proton - |charge| e = p + |char

4.ISOTOPES:
1) Same atomic number but different atomic mass.
2) Same number of protons but different number of neutr