Chemestry chapter 1 and 2

THEORY

Dynamic ideas that explain observations, predict future results, and must be as simple as possible.

ATOM

The indivisible particle that is the smallest unit of matter.

LAW OF CONSERVATION OF MASS

States that atoms are neither created nor destroyed in a chemical reaction; they are simply rearranged.

LAW OF CONSTANT COMPOSITION

States that every compound has a fixed, definite composition.

ELECTRON

A negatively charged particle that is a fundamental part of an atom.

Nucleus

The positively charged center of an atom, containing protons and neutrons.

PROTON

The positively charged particle found in the nucleus of an atom.

NEUTRON

A heavy neutral particle found in the nucleus of an atom.

VALENCE ELECTRONS

Electrons located in the outermost energy level of an atom.

ATOMIC NUMBER (Z)

The number of protons in the nucleus of an atom, which determines the identity of the atom.

ATOMIC MASS (A)

The sum of the number of protons and neutrons in an atom.

ISOTOPES

Different forms of an element with the same number of protons but differing numbers of neutrons.

RADIOISOTOPES

Unstable isotopes that decay and emit radiation.

ION

An atom that has gained or lost electrons, resulting in a net charge.

CATION

A positively charged ion formed by losing electrons.

ANION

A negatively charged ion formed by gaining electrons.

OCTET RULE

Atoms seek to have a full valence shell of 8 electrons for stability.

IONIC BOND

A chemical bond formed through the transfer of electrons from one atom to another.

MOLECULAR COMPOUND

A compound made up of two or more non-metal atoms that share electrons.

ELECTRONEGATIVITY

The ability of an atom to attract and hold onto electrons.

POLYATOMIC IONS

Ions that consist of two or more atoms that are covalently bonded.

HYDRATE

A compound that contains water molecules within its structure.

ANHYDROUS

A compound that has had its water removed.

ELECTROLYTE

A substance that produces an electrically conducting solution when dissolved in water.

BONDING CAPACITY

The number of covalent bonds an atom can form based on its valence electrons.

DALTON

John Dalton proposed the atomic theory, which states that matter is made up of atoms, which are indivisible and that compounds are formed by a combination of different types of atoms.

THOMSON

J.J. Thomson discovered the electron and proposed the 'plum pudding' model of the atom, which describes the atom as a positively charged sphere with negatively charged electrons embedded within.

RUTHERFORD

Ernest Rutherford conducted the gold foil experiment, discovering the nucleus of the atom and proposing that atoms consist mostly of empty space with a dense, positively charged nucleus.

BOHR

Niels Bohr proposed the Bohr model of the atom, suggesting that electrons orbit the nucleus at fixed distances and can jump between these orbits when energy is absorbed or emitted.

SCHRÖDINGER

Erwin Schrödinger developed the quantum mechanical model of the atom, emphasizing the probabilistic nature of electron positions and energy levels.