Atoms and Atomic Structure 2

Proton

1. A positively (+) charged subatomic particle located in the nucleus of an atom. 2. The number of protons determines the atomic number of an atom and identifies what element it is. 3. Like a neutron, it is one of the two particles types in the nucleus that contribute to the atomic mass of atoms.

Neutron

1. A sub-atomic particle similar in size to a proton and also found nucleus of an atom that has no (0) electric charge when compared to a proton or electron. 2. Like a proton, it is the other of the two types of particles that contribute to the mass of an atom.

Subatomic Particles

1. Particles that are smaller than the atom. 2. Usually referring to the components of an atom, Protons, Neutrons, and Electrons. 3 Any of the many particles in the universe that are smaller than an atom

Atom

1. The smallest unit of matter in any element. 2. The smallest unit of matter. 3. The smallest unit of chemistry.

Electrical Charge

A form of electric charge, designated negative, positive, or neutral (meaning without charge) that is found on the subatomic particles that make up all atoms.

Electron

A negatively charged subatomic particle located in the electron cloud outside the nucleus. It determines how atoms combine with other atoms.

Bohr Model

A simple model of the atom contains a positively charged nucleus orbited by negatively charged electrons in specific orbital shells or energy levels.

Atomic Number

A unique number for each element on the periodic table that is equal to the number of protons in any atom of that element. 2.Identifies the element ex. Hydrogen = 1 proton.

Atomic Mass

The number of protons and neutrons in the nucleus of an atom. (The number of neutrons may differ from atom to atom causing the mass to be a non-whole number on the Periodic Table)

Nucleus

The tiny, very dense, positively charged region in the center of an atom made up of protons and neutrons. The number of protons and neutrons in the nucleus determines the atomic mass of and element on the Periodic Table.

Neutral Atom

an atom that has an equal number of protons and electrons

Atomic Models

representations of different theories showing what an atom may look like. Has been updated based on new information many times.

radiactive decay

the breakdown of the atoms that are isotopes releasing matter and energy

half-life of an isotope

the rate of decay of an isotope (50% over a given time)

Electron Cloud (model)

the the area outside of the nucleus of an atom that surrounds it showing where electrons are most likely to be found. (each dot represents a POSSIBLE electron position)