Intro to chemistry, water properties & pH

element

A substance that cannot be broken down into simpler substances by chemical means. Made up of only one atom

Atom

The basic unit of a chemical element, consisting of a nucleus surrounded by electrons.

Positive charge

Protons found in the nucleus

Neutral charge

Neutrons found in the nucleus

Negative charge

Electrons found orbiting the nucleus in “shells”

Atomic number

Number of protons in the nucleus

Atomic mass

Equivalent to the number of protons & neutrons

Neutral atoms

Same number of protons as electrons

Isotopes

Atoms of the same element that have different numbers of neutrons

Radiometric dating

Radioactivity in carbon found in fossils to see how old the fossil is

Bonds

How atoms stick together to form bigger things called molecules or compounds

Molecules

Specific compounds with distinct properties

Compounds

Two or more elements chemically joined together

Valence electrons

Number of electrons on the last shell

Chemical bonds

Atoms in compounds that are being held together

Ionic bonds

Stealing electrons from another atom to fill it’s outer shell

Ions

Can either be positively or negatively charged if you gain or lose electrons. Losing = positive and stealing = negative

Covalent bonds

When an outer electron is shared between two atoms

Single covalent bond

2 electrons being shared

Double covalent bond

4 electrons being shared

Triple covalent bond

6 electrons being shared

Polar molecules

Contains a negative and positive side due to unequal sharing of electrons.

Adhesion

Water sticking to other things

Cohesion

Water sticking to itself

High surface tension

Hydrogen bonds stick together at the surface creating a resistant barrier at the surface

Universal solvent

A substance that can dissolve polar and ionic compounds

Hydrophobic

Substances that repel water or do not mix with water

Hydrophilic

Substances that are attracted to water and can easily mix or dissolve in it

Solutions

A type of mixture involving a solvent and a solute

Solute

A substance that gets dissolved

Solvent

The substance that dissolves the solute

Mixtures

A physical blend of 2 or more substances

Acids

pH level of below 7

Acid reactions

Can taste sour or be corrosive

Bases

pH above 7

Bases reactions

Taste bitter and feel slippery

pH

Potential hydrogens

H+

Hydrogen ions

OH-

Hydroxide ions

pH scale multiplies by

10 and stacks

Ocean acidification reasons

Uptake of carbon dioxide and acid rain

Acid rain

Air pollution effecting the rainwater

Indicator

Any substance that gives a visible sign usually by a color change

Acidic colors

Red, orange, yellow

Neutral colors

Green

Basic colors

Blue and purple