rt chapter 8

matter

anything that occupies space and has shapenor form

mass

quantity of matter that makes up any physical object

atoms

building blocks of matter

neutrons protons electrons

particles that compose atoms:

neutrons protons

together form the nucleus of the atom

electrons

circlr the nucleus in orbits called shells

niels bohr

he describe the miniature solar in 1913 known as Bhor’s atom

electron

very small particle carring one unit of negative electric charge (1.602×10^-19)

9.1×10^-31 kg

mass of electron

0

atomic mass of electron

Joseph John Thomson

discovered electrons

neutron

electrically neutral (no charge)

1.675×10^-27 kg

mass of neutron

1

atomic mass number of neutron

James Chadwick

discovered neutrons

protons

carries all the atoms positive electrical charge (1.602×10^-19)

1.673×10^-27 kg

mass of proton

1

atomic mass number of proton

Eugen Goldstein

discovered protons

elements

substances made up of only ond type of atom

molecules

two or more atoms may combine chemically

chemical compound

consists of only ome type of molecule

mixtures

substances that contain more than one type of molecule

ionization

a process when a neutral atom gains or loses an electron.