TEAS CHEM

🔬 ATOMIC STRUCTURE

Q: What are the three parts of an atom?
A: Protons, neutrons, electrons

Q: What is the charge of a proton?
A: Positive (+)

Q: What is the charge of a neutron?
A: Neutral (no charge)

Q: What is the charge of an electron?
A: Negative (–)

Q: Where are protons and neutrons located?
A: In the nucleus

Q: Where are electrons located?
A: Orbiting in shells around the nucleus

Q: Which subatomic particle is ~2000x smaller than a proton?
A: Electron

Q: What determines the identity of an element?
A: Number of protons

Q: What is the atomic number?
A: Number of protons

Q: What is atomic mass?
A: Protons + neutrons

Q: Why are electrons not included in atomic mass?
A: They have negligible mass

🔄 ISOTOPES

Q: What is an isotope?
A: Same element with different number of neutrons

Q: Do isotopes have different numbers of protons?
A: No

Q: Example of isotopes of carbon?
A: Carbon-12 and Carbon-14

⚡ IONS

Q: What is an ion?
A: Atom that gained or lost electrons

Q: What is a cation?
A: Positive ion (lost electrons)

Q: What is an anion?
A: Negative ion (gained electrons)

Q: What happens if electrons > protons?
A: Negative charge

Q: What happens if protons > electrons?
A: Positive charge

Q: What happens if protons = electrons?
A: Neutral atom

📊 PERIODIC TABLE

Q: How are elements arranged?
A: By increasing atomic number

Q: What are columns called?
A: Groups

Q: What are rows called?
A: Periods

Q: What do groups indicate?
A: Number of valence electrons

Q: What do periods indicate?
A: Number of energy levels (shells)

Q: What are the first two columns?
A: Alkali and alkaline earth metals (active metals)

Q: What are the middle elements?
A: Reactive metals (transition metals)

Q: What are far-right elements?
A: Noble gases (inactive)

Q: What is the integer on periodic table?
A: Atomic number

Q: Why is atomic mass a decimal?
A: Average of isotopes

🔋 VALENCE ELECTRONS

Q: What are valence electrons?
A: Electrons in outermost shell

Q: Why are valence electrons important?
A: They determine reactivity

Q: When are atoms most stable?
A: Full valence shell

🌀 ORBITALS

Q: What are orbitals?
A: Areas where electrons are found

Q: Max electrons in s orbital?
A: 2

Q: Max electrons in p orbital?
A: 6

Q: Max electrons in d orbital?
A: 10

Q: Max electrons in f orbital?
A: 14

Q: Order orbitals fill?
A: s → p → d → f

🔗 CHEMICAL BONDS

Q: What is an ionic bond?
A: Transfer of electrons

Q: Between what types?
A: Metal + nonmetal

Q: What is a covalent bond?
A: Sharing electrons

Q: Between what types?
A: Nonmetal + nonmetal

Q: What is electronegativity?
A: Attraction for electrons

Q: High electronegativity → what type of bond?
A: Ionic

Q: Low electronegativity → what type?
A: Covalent

⚖ MATTER & PROPERTIES

Q: What is matter?
A: Anything with mass and volume

Q: What is mass?
A: Amount of matter

Q: What is volume?
A: Space occupied

Q: What is density?
A: Mass ÷ volume

Q: Units of density?
A: g/L or kg/m³

Q: What affects density?
A: Temperature

🌡 STATES OF MATTER

Q: 4 states of matter?
A: Solid, liquid, gas, plasma

Q: Solid properties?
A: Fixed shape & volume

Q: Liquid properties?
A: Fixed volume, variable shape

Q: Gas properties?
A: No fixed shape or volume

Q: Plasma?
A: Ionized gas

🔄 PHASE CHANGES

Q: Solid → liquid?
A: Melting

Q: Liquid → solid?
A: Freezing

Q: Liquid → gas?
A: Evaporation

Q: Gas → liquid?
A: Condensation

Q: Solid → gas?
A: Sublimation

Q: Gas → solid?
A: Deposition

Q: Are phase changes reversible?
A: Yes

⚛ CHEMICAL REACTIONS

Q: Reactants are?
A: Starting substances

Q: Products are?
A: Substances formed

Q: Arrow means?
A: Yields/reacts to form

⚖ BALANCING EQUATIONS

Q: What must be equal on both sides?
A: Number of atoms

Q: What is a coefficient?
A: Number in front multiplying compound

🧮 MOLES

Q: What is a mole?
A: Unit for amount of substance

Q: What can it measure?
A: Atoms, molecules, or mass

🚀 REACTION RATES

Q: What is reaction rate?
A: Speed of reaction

Q: What increases reaction rate?
A: Temperature, concentration, catalysts

🔥 REACTION TYPES

Q: Endothermic?
A: Absorbs heat

Q: Exothermic?
A: Releases heat

⚖ EQUILIBRIUM

Q: What is equilibrium?
A: Forward = reverse rate

Q: Dynamic equilibrium?
A: Continuous reactions both ways

Q: Static equilibrium?
A: No change

⚡ CATALYSTS

Q: What is a catalyst?
A: Speeds reaction without being used

Q: How?
A: Lowers activation energy

💧 WATER PROPERTIES

Q: Why is water polar?
A: Uneven charge distribution

Q: Oxygen charge?
A: Slight negative

Q: Hydrogen charge?
A: Slight positive

🤝 COHESION & ADHESION

Q: Cohesion?
A: Water sticks to water

Q: Adhesion?
A: Water sticks to other substances

🧪 SOLUTIONS

Q: Solvent?
A: Dissolves substance

Q: Solute?
A: Gets dissolved

Q: Hydrophilic?
A: Water-loving

Q: Hydrophobic?
A: Water-fearing

🌡 SOLUBILITY

Q: What is solubility?
A: Ability to dissolve

Q: What increases solubility?
A: Temperature (usually)

📏 CONCENTRATION

Q: What is concentration?
A: Amount of solute in solvent

Q: What is dilution?
A: Adding solvent to lower concentration

Q: Molarity formula?
A: M = moles / liters

🚶 TRANSPORT

Q: Diffusion?
A: High → low concentration

Q: Osmosis?
A: Water movement only

Q: Passive transport requires?
A: No energy

Q: Active transport?
A: Low → high (needs energy)

🧪 ACIDS & BASES

Q: Acid?
A: Increases H⁺

Q: Base?
A: Decreases H⁺

Q: pH scale range?
A: 0–14

Q: Neutral pH?
A: 7

Q: Acidic pH?
A: <7

Q: Basic pH?
A: >7

🧬 BUFFERS

Q: What is a buffer?
A: Resists pH change

Q: Example?
A: Blood

⚖ NEUTRALIZATION

Q: Neutralization reaction?
A: Acid + base → water + salt

 ATOMIC STRUCTURE (MUST KNOW)

⚡ Core Rules

• Atomic number = protons

• Mass number = protons + neutrons

• Electrons determine charge, NOT identity

⚡ Charges

• Protons = +

• Electrons = –

• Neutrons = 0

👉 Quick logic:

• More electrons → negative ion (anion)

• More protons → positive ion (cation)

❗ Common Question

Q: What determines the element?
A: Number of protons

📊 PERIODIC TABLE (HIGHLY TESTED)

⚡ Structure

• Rows = Periods → energy levels

• Columns = Groups → valence electrons

⚡ Key Patterns

• Left → metals

• Right → nonmetals

• Far right → noble gases (stable)

⚡ Valence Electrons

• Group 1 → 1 valence electron

• Group 2 → 2

• Group 17 → 7

• Group 18 → 8 (full = stable)

❗ Common Questions

Q: Why are noble gases unreactive?
A: Full valence shell

Q: What increases across a period?
A: Atomic number

🌀 ORBITALS (MEMORY)

👉 2 – 6 – 10 – 14 rule

• s = 2

• p = 6

• d = 10

• f = 14

🔗 BONDS (VERY IMPORTANT)

Ionic vs Covalent

⚡ Key Concept

• Atoms bond to become stable (full valence shell)

❗ Common Question

Q: What type of bond is NaCl?
A: Ionic

⚖ MATTER & DENSITY

Formula:

👉 Density = mass ÷ volume

⚡ Key Concept

• Heat ↑ → density ↓

• Cold ↑ → density ↑

❗ Common Question

Q: Why does hot water rise?
A: Less dense

🌡 STATES OF MATTER

❗ Common Question

Q: Which is most compressible?
A: Gas

🔄 PHASE CHANGES (VERY COMMON)

👉 Memorize this chart:

• Melting = solid → liquid

• Freezing = liquid → solid

• Evaporation = liquid → gas

• Condensation = gas → liquid

• Sublimation = solid → gas

• Deposition = gas → solid

⚛ CHEMICAL REACTIONS

⚡ Basics

• Reactants → Products

• Arrow = “yields”

⚖ BALANCING RULE

👉 MUST have same number of atoms on both sides

❗ Common Question

Q: What can you change when balancing?
A: Coefficients ONLY

🧮 MOLES (BASIC IDEA)

• Used to measure quantity

• Helps compare amounts in reactions

🚀 REACTION RATES

Increase rate by:

• ↑ Temperature

• ↑ Concentration

• Add catalyst

🔥 ENERGY REACTIONS

• Endothermic → absorbs heat

• Exothermic → releases heat

❗ Easy Trick

• “Endo” = enter heat

• “Exo” = exit heat

⚖ EQUILIBRIUM

• Forward = reverse rate

• System looks stable but still reacting

Shift Rule:

• Add reactant → shift RIGHT

• Remove reactant → shift LEFT

⚡ CATALYSTS

• Speed up reactions

• Lower activation energy

• Not used up

💧 WATER (VERY TESTED)

Polarity:

• Oxygen = slightly negative

• Hydrogen = slightly positive

Effects:

• Makes water a universal solvent

🤝 COHESION vs ADHESION

• Cohesion → water sticks to water

• Adhesion → water sticks to other surfaces

🧪 SOLUTIONS

• Solvent = dissolves (water)

• Solute = gets dissolved

Types:

• Hydrophilic → dissolves

• Hydrophobic → does NOT dissolve

📏 CONCENTRATION

👉 Molarity = moles / liters

Dilution:

• Add solvent → concentration ↓

🚶 TRANSPORT (VERY IMPORTANT)

Passive (NO energy)

• Diffusion → high → low

• Osmosis → water movement

Active (USES energy)

• Low → high

❗ Common Question

Q: Difference between diffusion & osmosis?
A: Osmosis = water only

🧪 ACIDS & BASES (ALWAYS TESTED)

Definitions

• Acid → increases H⁺

• Base → decreases H⁺

pH SCALE

⚡ Key Concept

• More H⁺ = more acidic

❗ Common Question

Q: Is pH 3 acidic or basic?
A: Acidic

🧬 BUFFERS

• Resist pH change

• Keep body stable

👉 Blood = key example

⚖ NEUTRALIZATION

👉 Acid + Base → Water + Salt

🚨 LAST-MINUTE “YOU WILL SEE THIS” LIST

Focus HARD on these:

• Atomic number vs mass

• Ions (cation vs anion)

• Periodic table groups & valence electrons

• Ionic vs covalent bonds

• Density formula

• Phase changes

• Balancing equations

• Diffusion vs osmosis vs active transport

• pH scale

• Acid vs base

⚡ 10-SECOND MEMORY DUMP (RIGHT BEFORE TEST)

• Proton = identity

• Valence = reactivity

• Ionic = transfer / Covalent = share

• Density = m ÷ v

• Gas = most compressible

• Osmosis = water

• Active = energy

• Acid = H⁺

• pH < 7 = acidic

• Balance = coefficients only