TOPIC 1: STRUCTURE OF WATER AND HYDROGEN BONDING

Matter

Anything that takes up space and has mass

Element

A substance that cannot be broken down into other substances by chemical reactions

Compound

A substance consisting of two or more different elements combined in a fixed ratio

Essential elements

Carbon, hydrogen, oxygen, phosphorus, and nitrogen that makes up 96% of living matter

Trace elements

Elements that are required by an organism in very small quantities

Atomic number

Number of protons

Atomic mass

Protons + Neutrons averaged all over the isotopes

Group

Elements in the same vertical column have the same number of valence electrons

Period

Elements in the same horizontal row have the same total number of electron shells

Bohr Model

Shows electrons orbiting the nucleus of an atom

Lewis Dot Model

Simplified bohr diagram

Octet rule

Elements will gain, lose, or share electrons to become stable

Chemical bonds

An attraction between two atoms sharing or transferring valence electrons

Covalent bonds

When two or more atoms share electrons

Nonpolar covalent

Electrons shared equally between two atoms

Polar covalent

Electrons not shared equally between two atoms

Ionic bonds

The attraction between oppositely charged atoms (ions)

Cation

Positively charged ion

Anion

Negatively charged ion

Hydrogen bonds

Partially positive hydrogen atom in one polar covalent molecule will be attracted to an electronegative atom in another polar covalent.

Intermolecular bonds

Bonds that forms between molecules

Hydrogen is…

Partial positive charge

Electronegative atoms is…

Partial negative charge

What happens when a hydrogen atom is bonded to an electronegative atom?

The electron s are not being shared equally

Polarity

Unequal sharing of electrons = polar molecule

Cohesion

Attraction of molecules for other molecules of the same kind

Adhesion

The clinging of one molecule to another

Capillary action

The upward movement of water due to the forces of cohesion, adhesion, and surface tension

High specific heat

Water resists changes in temperature

How do specific heat doesn’t change the temperature in water?

Hydrogen bonds

What are the importance of high specific heat?

Moderates air temperature and stabilize ocean temperature

Evaporative cooling

High heat or vaporization

What are the importance of evaporative colling?

Moderates, stabilizes, and prevents

Density (Floating ice)

Water to ice expands and become less dense

Solvent

Dissolving agent in a solution

Water is a…

Versatile solvent

Solution

Homogenous mix of 2+ substances

Solute

Substance that is dissolved