chapter 3.1: What’s the Matter? Living and Nonliving Material

Matter

Which makes up everything around you, exists in three basic forms or states: solid, liquid, and gas.

law of conservation of matter

Every atom of matter that exists now on Earth has always existed and will always exist.

atom

Is the smallest bit of matter that represents one of the elements on the periodic table of elements.

subatomic particles

Each atom is composed of these.

nucleus (or center)

The nucleus of an atom is composed of subatomic particles called protons and neutrons.

electron shell

The nucleus (or center) of an atom is surrounded by at least one electron shell.

atomic number

Each element on the periodic table is defined by its number of protons, which is its atomic number.

protons, neutrons and electrons

Protons have a positive or +1 electrical charge, neutrons have a neutral or zero charge, and electrons have a negative or -1 charge.

ion

During some chemical interactions, an atom may lose or gain electrons and become an atom with a plus or minus electrical charge.

molecules

In order for atoms to construct matter large enough for you to see or feel, they have to combine with other atoms to form molecules.

compounds

Atoms combine with atoms of other elements to form compounds.

atomic bonds

To form molecules, atoms must exchange or share electrons from their outer electron shell to create atomic bonds.

ionic bond

Occurs when one atom gives an electron to another atom.

ionic compounds

Atoms linked together in this way are called ionic compounds.

Covalent bonding

When two atoms join together in a covalent bond, they form a molecule that shares electrons.

octet rule

To help predict which atoms are likely to form covalent bonds, scientists use the octet rule.

hydrogen bond

Results when some of the atoms in a covalently bonded molecule pull the shared electrons to one side of the molecule, creating an electrical imbalance in the molecule.

electronegativity

The ability to pull shared electrons towards themselves. This allows for the electron imbalance that creates hydrogen bonding.

polar or to exhibit polarity

When an imbalance of electrical charge occurs within a molecule, the molecule is said to be polar or to exhibit polarity.

oxidation

A chemical reaction where an atom takes or captures electrons from another nearby atom.

ionic bond or covalent bond

A bond in which electrons have been redistributed from one element to another but the overall charge for the molecule does not change.

reduction

The reverse of oxidation where an atom captures an electron from another one.

Acting as a solvent

The polarity of water molecules allows water to dissolve substances.

Creating surface tension

Water molecules cling together as a result of hydrogen bonding due to their polarity, creating a layer of bonded molecules that form a barrier or film around the edge of water.

Moving upward with capillary action

The polarity of water causes it to be attracted to slightly polar or charged materials, allowing water to move upward.

solvent

A liquid that dissolves or breaks down a solid when it touches that solid.

surface tension

A layer of bonded water molecules that form a barrier or film around the edge of water.

capillary action

The movement of water upward because its polarity attracts it to slightly polar or charged materials.

density

The relationship between an amount of matter and the space it occupies.

grams per cubic centimeter (g/cm3)

The unit usually used to measure density.

acid

A compound that gives away or releases a hydrogen ion (H+) during a chemical reaction.

base

A compound that captures a hydrogen ion during a chemical reaction.

SOLUTION

The slight polarity of a water molecule makes it a powerful agent for dissolving acid and base compounds into liquid form, or solution.

pH Scale

Measures how acidic a solution is; it ranges from 1 to 14.

acidity, base

Lower numbers on the pH scale indicate higher levels of acidity, while higher numbers indicate more base.

Biological molecules (or organic matter)

Make up a major component of the environment. Constructed of atoms and molecules, organic matter follows the same rules of chemical bonding.

Organic compounds

Are the basis for all living matter on Earth.

molecules

Are based on the unique ability of carbon atoms to create covalent bonds with multiple other atoms at the same time.

organic chemistry

The scientific subdiscipline of chemistry that studies carbon-based molecules.