8.5A Atomic Structure, 8.5B Protons and Electrons (charges)

Electron (e-)

1. A negatively (-) charged subatomic particle located in the electron cloud outside the nucleus. 2. It determines how atoms combine with other atoms. 3. Found outside of nucleus (on e-shells) 4. Very small and has virtually no mass. 0 AMU

Proton (p+)

1. A positively (+) charged subatomic particle located in the nucleus of an atom. 2. Determines the atomic number of an atom 3. Identifies what element it is. 4. Like a neutron, it is one of the two particles in the nucleus that contribute to the atomic mass. 5.One Proton is equal to 1 AMU

NEUtron

1. A sub-atomic particle similar in size to a proton and also found nucleus of an atom. 3. NEU-tral in charge (no charge) 2. Like a proton, it is the other of the two types of particles that contribute to the mass of an atom. 3. Equal to 1AMU

Nucleus

1. Center of an atom. 2. Made up of Protons and Neutrons 3. The number of protons and neutrons in the nucleus determines the MASS Number of elements on the Periodic Table.

Valence Electrons

1. Electrons found on the last (or outermost) energy level of an atom. 2. Influences how an element will react with other substances. 3. Elements with the same number of valence electrons have similar chemical properties and reactivity.

Subatomic Particles

1. Particles that are smaller than the atom. 2. Protons, Neutrons, and Electrons.

Atomic Mass (Mass Number)

1. The number of protons and neutrons in the nucleus of an atom. 2. All MASS is in the center of the atom (in the nucleus)

Atom

1. The smallest unit of matter in any element. 2. The smallest indivisible piece of matter. 3. It is comprised of even smaller sub-atomic particles called Protons, Neutrons, and Electrons.

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. Neutrally charged (equal amount of p+ and e-) Negatively charged (more e- than p+) Positively charged (more p+ than e-)

Oxygen

A gas with 8 neutrons.

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.

Atomic Mass Unit

AMU

Neon

An element with 10 neutrons

Mercury

An element with 80 electrons

Copper

One more proton than Nickel and one fewer proton than Zinc

Reactivity

Rate at which a chemical substance tends to undergo a chemical reaction; significantly influenced by valence electrons of the reacting substances.

Atomic Number

The number of protons in the nucleus of one atom of the element.

Net Charge

The sum of negative and positive charges.

Energy Levels (e-shells)

There may be no more than two electrons in the first shell, no more then eight electrons in the second shell and no more than eight electrons on the third shell.Some call this the 2-8-8 rule because these numbers match the number of elements in each row of the periodic table.

Neutral Atom

an atom that has an equal number of protons and electrons Total Charge = 0

A = P = E

stands for... Atomic Number = # of Protons = # of Electrons (in a neutral atom)

M-A=N

Mass Number - Atomic Number = # of Neutrons

Hydrogen

Element with no neutrons in nucleus

Helium

Heaviest element to have electrons only in one energy level