MYP Biology 9 HL Unit 2

Covalent Bond

Occurs when electrons are shared between two atoms

Isotope

Atoms of the same element that have same numbers of protons but different numbers of neutrons

Surface Tension

Caused by cohesion, allows the uppurmost molecules to create a type of thin surface

Duet Rule

Hydrogen and Helium need 2 electrons in their outermost shell to become stable

5. Draw and label the molecules and partial charges of a water molecule. Also be able to correctly place hydrogen bonds.

Compare drawing to image --->

Anion

Negatively charged ion

Atomic number

Number of protons

Heat Capacity (water)

Water can absorb a high amount of heat energy with only a small change in temperature

Hydrogen Bond

Forms between molecules that contain a hydrogen atom in a polar covalent bond. Hydrogen atom will have a slightly positive charge.

Matter

Anything that has mass and takes up space

List the 7 properties of water

Cohesion, adhesion, universal solvent, polarity, heat capacity, and surface tension, and hydrogen bonding

Adhesion

Sticks to other charged molecules

Cation

Positively charged ion

Cohesion

Sticks to itself

Electron

Negatively charged subatomic particle, revolving around an atom Mass 0 amu

Element

A substance that cannot be broken down into simpler substances

Ion

A charged atom

Ionic Bond

Electrons are transferred from one atom to another. One atom loses electrons, and one atom gains

Mass number

sum of the number of protons and neutrons

Nucleus

Center of an atom

Proton

Positively charged subatomic particle in the nucleus of an atom. Mass 1 amu

Universal solvent

Ability to dissolve many different solutes

Mass

The amount of matter in an object

List the 4 elements most common in living organisms.

Carbon, Hydrogen, Oxygen, Nitrogen (CHON)

Explain why most atoms tend to interact with other atoms. Explain in terms of their outermost electrons.

Atoms need to fill up their outermost shell (8 vElectrons)to become stable, so they bond with other atoms and share electrons so that they become stable

Describe the octet rule.

An atom can gain, lose, or share electrons to obtain 8 electrons in their outermost shell.

Define polarity.

Atoms share electrons unevenly because some atoms attract more strongly than others

Why is water a polar molecule?

Water is a polar molecule because it does not share its electrons equally.

Which partial charges are on the hydrogen atoms in water?

Partial positive charges.

Which partial charge is on the oxygen atom in water?

Partial negative charge.