Chemistry Form 4: Chapter 2 - Structure of an Atom

   

• Atom consists of electrons surrounding a nucleus that contains protons and neutrons.
• Electrons are arranged around the nucleus in energy levels or shells. 
• The mass of an atom is concentrated in nucleus which contained the protons and neutrons.
• The nucleus is positively charged because of the presence of protons which are positively charged and the neutrons are neutral.
• The atom is neutral because the number of protons and the number of electrons are equal

Subatomic particles	Symbol	Relative mass	Relative   charged	Position
Proton	P	1	+1	Nucleus
Neutron	N	1	0
Electron	e-	1/1837 » 0	-1	Orbit

Symbol of Element