Biology chapter 2

Atom

Simplest particle of an element that retains the properties of that element

Atomic Number

The number of protons in the nucleus of an atom

Bond

Made up of two or more types of atoms chemically combined- attractive forces that hold atoms together

Chemical Reaction

Process that changes one set of chemicals into another set of chemicals

Compound

Two or more atoms in fixed proportions

(Made up of two or more types of atoms chemically combined (bonded))

Chemistry

The study of the behavior of matter

Covalent Bond

When 2 atoms share 1 or more pairs of electrons

Electron

-A subatomic particle that has a negative charge

-Number may change during chemical reactions

-No mass

Element

Substances that cannot be broken down chemically into simpler kinds of matter

Energy level

-Place in an atom where the electrons are found

-Not well defined path; regions (clouds) where electrons are expected to be

-Energy level closest to nucleus fills first, holds electrons with lowest energy, and holds a maximum of 2 electrons

Ion

A charged atom

(Happens because of a difference in the # of protons and electrons)

Ionic Bond

-Attraction of two oppositely charged atoms

-Happens between a metal and a nonmetal

-Atoms giving and losing electrons

Mass

Amount of matter in an object

Matter

Anything that has mass and takes up space

Molecule

Simplest part of a substance that retains all the properties of that substance and can exist in a free state

Neutron

-A subatomic particle that has no charge

-Has a mass of 1

-Found in nucleus

-Number never changes during chemical reactions

Nucleus

-Center of an atom

-Most dense part of an atom, holds majority of the mass

-Contains protons and neutrons

Proton

-Subatomic particle with a positive charge

-Mass of 1

-Found in nucleus

-Number never changes during a chemical reaction

Valence electron

-An electron that is found in the outermost shell of an atom and that determines the atom's chemical properties and reactivity

-Atoms try to make their valence electron level full to become stable

Isotope

Atoms of the same element with different number's of neutrons and mass

Charge-Cloud Model/ Quantum Mechanical model

Current atomic model by Heisenberg

• based off of uncertainty principle

-Electrons found in clouds

Law of conservation of matter

Matter is not created nor destroyed in any chemical or physical change

Periodic Table

-A chart of the elements showing the repeating pattern of their properties

-Groups/families (columns) are vertical and they tell you how many valence electrons are in an atom

-Periods (rows) are horizontal and they tell how many energy levels/electron shells an atom has

Activation Energy

The energy needed to be gained by the reactants to become intermediates in a reaction

Energy in reactions

Reactants→Intermediates→Products

-intermediates ALWAYS have more energy than the reactants

-Reactants have to gain energy to become intermediates (Activation energy)

Endergonic reaction

A reaction where the products energy is more than the reactant's energy

(energy is gained)

Exergonic Reactions

A reaction where the product's energy is less than the reactant's energy

(energy is released)

Catalyst

-Substance that reduces the amount of energy required to make a reaction

-Changes in activation energy and rate of reaction

-No changes in identity of reactants or products or of catalysts

-Commonly called enzymes

-Catalysts can be reused

Reactant

A chemical substance that is present at the start of a chemical reaction

Product

A substance that forms in a chemical reaction/ the substance the reactants become

OIL RIG

Oxidation Is Loss, Reduction Is Gain

-Oxidation is loss of electrons

-Reduction is gain of electrons

-One can't happen without the other

Oxidation Reaction

Chemical reaction where a reactant loses one of more electrons, becoming more positive in charge

Reduction Reaction

A chemical reaction in which a reactant gains one or more electrons, becoming more negative in charge

States of matter and what temperature they melt/freeze and evaporate/condensate at

Solid, liquid, gas

Melts/Freezes at 0° Celsius

Evaporates/Condenses at 100° Celsius

Types of Mixtures

Solutions, Colloids, and suspensions

Solution

-Homogenous mixture

-Stays mixed and clear

-Particles are small enough to stay mixed

Colloid

-Heterogenous mixture

-Stays mixed/cloudy

-Particles big enough to be cloudy

-Particles also small enough to stay mixed

-Sols and Gels

Suspension

-Heterogenous mixture

-Separates

-Particles are suspended

-If you stop giving it energy particles will fall

-Particles big enough to block light

Sols

Colloids that are semi-liquids

Gels

Colloids that are semi-solids

Solutions are always made of

Solvent+Solute

Solvent

Material in greater amount

Solute

Material in lesser amount

Aqueous solution

Where water is the solvent

Why does water have a bent molecular shape

Because of electron pair repulsion

Water is inorganic or organic

Inorganic

Biological chemistry is ___________ based chemistry

Water based chemistry

Polarity

Uneven distribution of electrons

(uneven distribution of charge)

-Can apply to individual bonds or molecules as a whole

Why is water polar

The oxygen atom has a slight negative charge and the 2 hydrogen atoms have a slight positive charge

Hydrogen Bonding

The attraction between a partially positive hydrogen on one molecule and a partially negative other atom on another molecule

-Partially negative atom usually= Oxygen, Nitrogen, or Fluorine because they are electron hogs

Water's hydrogen bonding

-Happens between two water molecules

-Partially negative hydrogen of one water molecule attracted to partially positive oxygen of another water molecule

Cohesion

Water molecules sticking to other water molecules