Atomic structure and Electron arrangement

Protons

Positively charged particles found inside the nucleus of an atom. Mass no. is 1 and the charge is +1

Neutron

Neutral particles found inside the nucleus of an atom. Mass no. is 1 charge is 0

Electron

Negatively charged particles that orbit the nucleus of an atom. Mass number is 1/1838 charge is -1

Mass Number

The sum of protons and neutrons in an atom. Always the larger than the atomic number.

Atomic number

the amount of protons in an atom

Energy Level

the fixed energy value that an electron in an atom may have

Democritus

Ancient Greek philosopher that suggested that atom is the smallest part of matter and they were indivisible

Dalton

he developed an atomic theory: 1. all matter is made of tiny particles called atoms. 2. atoms are indivisible and indestructible. 3: atoms of the same element are identical

J.J. Thomson

discovered electrons using cathode ray tubes. suggested that electrons with negative charge are embedded in a sphere of positive charge (plum pudding model)

Rutherford

done the gold foil experiment and discovered that atom is mostly empty space with a positive charged nucleus (discovered protons)

Niels Bohr

suggested electrons orbited the nucleus in shells / energy levels

Chadwick

discovered the neutron

Millikan

discovered the magnitude of charge on the electron

Atomic Absorption Spectrometry

a technique used to identify and measure the concentration of a metal in a sample by measuring how much light its atom absorbs, used to detect alcohol and drugs in the blood.

Heisenberg’s Uncertainty principle

states that it is impossible to measure the exact velocity and exact position of the electron at the same time.

Orbital

a region in space around the nucleus which there is a high probability of finding an electron.

Sublevel

a subdivision of an energy level containing orbitals of similar energy.

Ion

an atom that has gained or lost electrons

isotopes

atoms of the same element which have a different mass number due to the number of neutrons.

Relative Atomic Mass

the average mass numbers of the isotopes of the element as they occur naturally. taking their abundances into account