TEAS CHEM

Parts of an atom

Protons, neutrons, electrons.

Charge of a proton

Positive (+).

Charge of a neutron

Neutral (no charge).

Charge of an electron

Negative (–).

Location of protons and neutrons

In the nucleus.

Location of electrons

Orbiting in shells around the nucleus.

Particle smaller than a proton

Electron (~2000x smaller).

Identity of an element

Determined by the number of protons.

Atomic number

Number of protons.

Atomic mass

Protons + neutrons.

Negligible mass

Electrons are not included in atomic mass.

Isotope

Same element with different number of neutrons.

Protons in isotopes

No, they have the same number of protons.

Isotopes of carbon

Carbon-12 and Carbon-14.

Ion

Atom that gained or lost electrons.

Cation

Positive ion (lost electrons).

Anion

Negative ion (gained electrons).

Electrons > protons

Negative charge.

Protons > electrons

Positive charge.

Protons = electrons

Neutral atom.

Arrangement of elements in periodic table

By increasing atomic number.

Columns in periodic table

Groups.

Rows in periodic table

Periods.

Groups indicate

Number of valence electrons.

Periods indicate

Number of energy levels (shells).

First two columns of periodic table

Alkali and alkaline earth metals (active metals).

Middle elements in periodic table

Reactive metals (transition metals).

Far-right elements in periodic table

Noble gases (inactive).

Integer on periodic table

Atomic number.

Why is atomic mass a decimal?

Average of isotopes.

Valence electrons

Electrons in outermost shell.

Importance of valence electrons

They determine reactivity.

Most stable atoms

Full valence shell.

Orbitals

Areas where electrons are found.

Max electrons in s orbital

2.

Max electrons in p orbital

6.

Max electrons in d orbital

10.

Max electrons in f orbital

14.

Order of orbital filling

s → p → d → f.

Ionic bond

Transfer of electrons.

Types in ionic bond

Metal + nonmetal.

Covalent bond

Sharing electrons.

Types in covalent bond

Nonmetal + nonmetal.

Electronegativity

Attraction for electrons.

High electronegativity bond type

Ionic.

Low electronegativity bond type

Covalent.

Matter

Anything with mass and volume.

Mass

Amount of matter.

Volume

Space occupied.

Density formula

Mass ÷ volume.

Units of density

g/L or kg/m³.

Factors affecting density

Temperature.

States of matter

Solid, liquid, gas, plasma.

Solid properties

Fixed shape & volume.

Liquid properties

Fixed volume, variable shape.

Gas properties

No fixed shape or volume.

Plasma

Ionized gas.

Solid to liquid phase change

Melting.

Liquid to solid phase change

Freezing.

Liquid to gas phase change

Evaporation.

Gas to liquid phase change

Condensation.

Solid to gas phase change

Sublimation.

Gas to solid phase change

Deposition.

Reversibility of phase changes

Yes.

Reactants in chemical reactions

Starting substances.

Products in chemical reactions

Substances formed.

Arrow in chemical equation

Yields/reacts to form.

Equality in balancing equations

Number of atoms must be equal on both sides.

Coefficient in balancing equations

Number in front multiplying compound.

What is a mole?

Unit for amount of substance.

What can a mole measure?

Atoms, molecules, or mass.

What is reaction rate?

Speed of reaction.

What increases reaction rate?

Temperature, concentration, catalysts.

Endothermic reaction

Absorbs heat.

Exothermic reaction

Releases heat.

What is equilibrium?

Forward = reverse rate.

Dynamic equilibrium

Continuous reactions both ways.

Static equilibrium

No change.

What is a catalyst?

Speeds reaction without being used.

How does a catalyst work?

Lowers activation energy.

Why is water polar?

Uneven charge distribution.

Charge of oxygen in water

Slight negative.

Charge of hydrogen in water

Slight positive.

Cohesion in water

Water sticks to water.

Adhesion in water

Water sticks to other substances.

Solvent

Dissolves substance.

Solute

Gets dissolved.

Hydrophilic substance

Water-loving.

Hydrophobic substance

Water-fearing.

What is solubility?

Ability to dissolve.

What increases solubility?

Temperature (usually).

What is concentration?

Amount of solute in solvent.

What is dilution?

Adding solvent to lower concentration.

Molarity formula

M = moles / liters.

Diffusion

High → low concentration.

Osmosis

Water movement only.

Passive transport

Requires no energy.

Active transport

Low → high (needs energy).

Acid definition

Increases H⁺.

Base definition

Decreases H⁺.