Chemistry Test 1

Matter

Anything that has mass and takes up space.

Atom

The smallest unit of matter.

Proton

Positively charged subatomic particles. Found in the nucleus of an atom.

Neutron

Neutral (no charge) subatomic particles. Found in the nucleus of an atom.

Electron

Negatively charged subatomic particles with almost no mass. Electrons orbit the nucleus of an atom on different energy levels.

Physical Property

The way something looks, feels, smells, etc. (Color, Size, Density, Luster, Malleability, Magnetism, Boiling Point, Melting Point, Solubility).

Chemical Property

Describe the ability of something to undergo different chemical changes (Flammability, Reactivity).

Chemical Change

Change in color, Change in Energy (Light, Heat), Change in Odor, Formation of a Gas or Solid.

Chemical Changes cannot easily be reversed (ex. wood ash from a bonfire).

Element

Unique atoms that make up a specific substance.

Periodic Table

Lists and organizes elements.

Chemical Symbol

One or two letters that represents an element on the periodic table.

Atomic Number

The number of protons an atom contains. Each element has a different number of protons.

Atomic Mass

The average mass of a typical atom of that element. (Protons and Neutrons). (Atomic Mass- Atomic Number = Number of Neutrons)

Period

A row of elements across the periodic table.

Group/Family

A column of elements in the periodic table. Groups/families have similar physical and chemical properties.

Energy Level

“Zones” or “Orbits” of electrons. 2, 8, 18, 32

Isotope

Atoms of the same element that have a different number of neutrons. (Atomic Mass changes).

Neutral Element

The number of protons is equal to the number of neutrons (net charge is zero).

Valence Electrons

Electrons on the outermost energy level of an atom. Valence electrons are the furthest away from the nucleus of an atom, so they are easily bonded/transferred during a chemical reaction.

Chemical Bond

When electrons from different atoms pair up, they form a chemical bond.

Ion

An atom that has a positive or negative charge (more or less electrons than the number of protons).

Cation

A positively charged ion.

Anion

A negatively charged ion.

Inert

Chemically inactive (does not react with other atoms).

Reactive

More likely to react with other atoms- can bond easily with other elements.

Lewis Dot Structure

A representation of the number of valence electrons in an atom.

Octet Rule

The theory that atoms tend to bond in a way that each atom has 8 electrons in its valence (outermost) energy level.

Bohr Model

A model of an atom that shows protons and neutrons at the center with electrons at various energy levels (orbits) around the nucleus.

Metal

A metal is a material that ***when polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well.***

Metalloid

A material that has characteristics of both metals and nonmetals.

Covalent Bond

A chemical bond that consists of the mutual sharing of one or more pairs of electrons between to atoms.

Ionic Bond

The attraction between two oppositely charged atoms. Valence electrons are permanently transferred from one atom to another.