Atomic Composition (Chem)

Atoms

Building blocks/particle of matter

Molecule

A group of atoms bonded together

Element

A pure substance made of only one kind of atom

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

Isotope

Atoms of the same element (same protons) that have different numbers of neutrons

Isotopic Notation

notation that shows the chemical symbol, atomic number, and mass number for an isotope of an element

atomic number

the number of protons in the nucleus of an atom

mass number

the sum of the number of neutrons and protons in an atomic nucleus

positive charge

more protons than electrons

negative charge

more electrons than protons

Ions

charged particles from the gain/loss of electrons

Cation

A positively charged ion

Anion

A negatively charged ion

average atomic mass

the weighted average of the atomic masses of the naturally occurring isotopes of an element

average atomic mass equation

average atomic mass = (% abundance¹ / 100) x mass¹ + (% abundance² / 100) x mass²

nucleus

Center of an atom

electron cloud

area around the nucleus of an atom where the atom's electrons are most likely to be found

are electrons part of the atomic mass? why?

No because their mass is practically 0

physical change

A change in a substance that does not involve a change in the identity of the substance

chemical change

A change that occurs when one or more substances change into entirely new substances with different properties.

Dalton's Atomic Theory

1) elements are composed of atoms. 2) atoms of same element are identical, but differ from other elements. 3) elements can mix together 4) atoms only change when mixed with other elements

dalton

Discovered atoms have different weights. A measure of mass for atoms and subatomic particles; the same as the atomic mass unit, or amu.

thompson

discovered the electron, plum pudding model

Rutherford

Gold foil experiment, discovered nucleus

Bohr

planetary model of the atom

Chadwick and Schrodinger

discovered the neutron, used properties of matter to construct wave mechanics, and learned that electrons do not have a specific orbit.