1 - 3 Atomic structure
● ***Atom: smallest unit of matter in chemistry; contains protons and electrons (and
sometimes neutrons......)
● ***Molecule: consists of ≥2 atoms chemically bonded by covalent bonds
Structure of an atom***
Atomic particle Relative mass Relative charge
proton 1 +1
neutron 1 0
electron (TB) 1/1836 -1
(SBA) 1/2000
● ***Atomic/proton number: number of protons/electrons in single atom (of element)
● ***Mass/nucleon number: number of protons + neutrons in single atom (of element)
● ***Isotope: atoms with same number of protons (i.e.: of same element) but different
number of neutrons
mass number of isotope × abundance(%)+......
● ***Relative atomic mass (Ar):
100
1
● ***Atom: smallest unit of matter in chemistry; contains protons and electrons (and
sometimes neutrons......)
● ***Molecule: consists of ≥2 atoms chemically bonded by covalent bonds
Structure of an atom***
Atomic particle Relative mass Relative charge
proton 1 +1
neutron 1 0
electron (TB) 1/1836 -1
(SBA) 1/2000
● ***Atomic/proton number: number of protons/electrons in single atom (of element)
● ***Mass/nucleon number: number of protons + neutrons in single atom (of element)
● ***Isotope: atoms with same number of protons (i.e.: of same element) but different
number of neutrons
mass number of isotope × abundance(%)+......
● ***Relative atomic mass (Ar):
100
1
