Atomic structure

Atoms consist of

Electrons

negative charge

Neutrons

Protons

positive charge

Isotopes

atoms of same element

same atomic number

same chemical properties

same electronic configuration of both isotopes

different number of neutrons

different physical properties

density

melting point

boilling point

Combines chemically

Molecules

of compounds

atoms of different elements

methane

ammonia

water

carbon dioxide

hydrochloric acid

of elements

atoms of same elements

nitrogen

hydrogen

oxygen

chlorine

phosphorus

Electronic configuration

electrons arranged around the nucleus in the shells of an atom

shells number 1,2,3 and so on

each shell can occupy a certain number of electrons

How to find electron configuration?

find the proton number of the atom

find the derived number of electrons

arrange electrons in shells

electrons start occupying new shells when previous ones are occupied

Valence electrons

find in outermost occupied shell of an atoms

outermost shell=shell furthest from the nucleus

nature of elements determined by the number of valence electrons

1-2 metallic

aliminium with 3 is an exception

4-8 non-metalic

Gains or loses electrons

Ions

Gain electrons

anions

non-metals

ions are negatively charged

Lose electrons

cations

metals

ions are positively charged

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