What is an atom?

fundamental building block of matter

Everything is made of atoms

elements are made of atoms

Smallest particle of an element that possesses the properties of the element

Subatomic Particles

Proton

found in nucleus

+1 charge

same mass as neutron

atomic number = number of protons

attracted to electron

Neutron

= to protons + electrons

same mass a proton

0 charge

separates protons

found in nucleus

Electron

neutral atom if number of protons is equal to electrons

almost 0 mass

-1 charge

found outside nucleus (electron cloud)