Chapter 2 - Bushong 10e

atom

indivisible

118

number of identified elements

subatomic particles

smaller than an atom

John Dalton

According to him, an element was composed of identical atoms that reacted the same way chemically

Dmitri Mendeleev

showed that if the elements were arranged in order of increasing atomic mass, a periodic repetition of similar chemical properties occurred

65

number of elements in Dmitri’s periodic table?

Halogens

Group VII elements, easily vaporized and comb9ine with metals to form water soluble salts

Noble gases

Group VIII elements, highly resistant to reaction with other elements

J.J. Thompson

Proposed that atoms are like plum pudding with the existence of electrons

Ernest Rutherford

disproved Thompson’s model and proposed a nuclear model and called the center of the atom, nucleus

Niels Bohr

his model was a miniature solar system in which the electrons revolved about the nucleus in prescribed orbits or energy levels.

Electron, Proton, Neutron

Three primary constituents of an atom

0

atomic mass number of electron

Chemical Element

The number of protons determines what?

Isotopes

same number of protons, different number of neutrons

34 eV

required energy for the xray to transfer energy

Principal Quantum Number

shell number by physicists