UPCAT Chemistry — Periodic Table, Bonding & Chemical LanguageCheat Sheet
Periodic Table, Bonding & Chemical Language cheat sheet for UPCAT aspirants. If you could only take one sheet of paper into your review session, this is what it would look like. University of the Philippines's most-tested concepts, all in one place.
Exam context
On the UPCAT 2026, the Chemistry subtest carries a "Core" weight in University of the Philippines's pattern. Periodic Table, Bonding & Chemical Language lands at position 3rd out of 7 in the standard review order. Target score is UPG ≤ 2.2 typical, and roughly 20 items come from Chemistry on a typical UPCAT paper.
Periodic Table, Bonding & Chemical Language - Cheat sheet
Your last-minute revision companion for mastering periodic trends, chemical bonding, and chemical nomenclature for UPCAT and other college entrance exams.
Sections
Common Values
Value
+1
Symbol
M+
Quantity
Group 1 ion charge
Value
+2
Symbol
M2+
Quantity
Group 2 ion charge
Value
-1
Symbol
X-
Quantity
Group 17 ion charge
Value
-2
Symbol
X2-
Quantity
Group 16 ion charge
Section Title
Periodic Table Trends
Important Facts
- Atomic radius DECREASES across period (left to right)
- Atomic radius INCREASES down group (top to bottom)
- Ionization energy INCREASES across period
- Ionization energy DECREASES down group
- Electronegativity INCREASES across period
- Electronegativity DECREASES down group
- Metallic character DECREASES across period
- Metallic character INCREASES down group
Key Definitions
Term
Atomic Radius
Example
Na > Mg > Al (decreases across period)
Definition
Distance from nucleus to outermost electron shell
Term
Ionization Energy
Example
He has highest, Fr has lowest
Definition
Energy needed to remove an electron from an atom
Term
Electronegativity
Example
F = 4.0 (highest), Cs = 0.7 (lowest)
Definition
Tendency of atom to attract electrons in a bond
Term
Electron Affinity
Example
Halogens have high electron affinity
Definition
Energy released when atom gains an electron
Diagrams To Know
- Periodic table with groups and periods labeled
- Trend arrows for atomic radius, ionization energy, electronegativity
Formulas
Formula
Formal Charge = V - N - B/2
Meaning
V=valence electrons, N=nonbonding electrons, B=bonding electrons
Watch Out
Count ALL electrons around atom, not just bonds
When To Use
To determine best Lewis structure among resonance forms
Section Title
Chemical Bonding Types
Important Facts
- Electronegativity difference > 1.7 = ionic bond
- Electronegativity difference 0.4-1.7 = polar covalent
- Electronegativity difference < 0.4 = nonpolar covalent
- Metals lose electrons to form cations (+)
- Nonmetals gain electrons to form anions (-)
- Octet rule: atoms want 8 valence electrons
- Hydrogen wants 2 electrons (duet rule)
Key Definitions
Term
Ionic Bond
Example
NaCl, CaF2, MgO
Definition
Electron transfer between metal and nonmetal
Term
Covalent Bond
Example
H2O, CH4, NH3
Definition
Electron sharing between nonmetals
Term
Metallic Bond
Example
Cu, Al, Fe
Definition
Electrons shared through sea of electrons between metals
Term
Polar Covalent
Example
H-Cl, H-O
Definition
Unequal sharing of electrons due to electronegativity difference
Diagrams To Know
- Lewis dot structures for common molecules
- Electron transfer diagrams for ionic compounds
- VSEPR molecular geometries
Common Values
Value
180°
Symbol
∠
Quantity
Linear bond angle
Value
120°
Symbol
∠
Quantity
Trigonal planar angle
Value
109.5°
Symbol
∠
Quantity
Tetrahedral angle
Value
104.5°
Symbol
∠
Quantity
Water bond angle
Section Title
Molecular Geometry (VSEPR)
Important Facts
- Lone pairs take up more space than bonding pairs
- Multiple bonds count as ONE electron region
- AX2 = Linear (180°)
- AX3 = Trigonal planar (120°)
- AX4 = Tetrahedral (109.5°)
- AX2E = Bent (104.5° for water)
- AX3E = Trigonal pyramidal (107° for ammonia)
- AX2E2 = Bent (104.5°)
Key Definitions
Term
VSEPR Theory
Example
Determines 3D shape of molecules
Definition
Electron pairs repel and arrange to minimize repulsion
Term
Bonding Pairs
Example
Single, double, triple bonds
Definition
Electron pairs shared between atoms
Term
Lone Pairs
Example
Two lone pairs on oxygen in water
Definition
Non-bonding electron pairs on central atom
Diagrams To Know
- Basic VSEPR geometries with bond angles
- 3D molecular shapes
- Electron vs molecular geometry diagrams
Section Title
Intermolecular Forces (IMFA)
Important Facts
- Strength order: Ion-Dipole > H-bonding > Dipole-Dipole > London Dispersion
- Larger molecules = stronger London forces
- Stronger IMFA = higher boiling point
- Stronger IMFA = lower vapor pressure
- Stronger IMFA = higher surface tension
- Stronger IMFA = higher viscosity
- Only H-F, H-O, H-N bonds can hydrogen bond
Key Definitions
Term
London Dispersion Forces
Example
CH4, He, all hydrocarbons
Definition
Temporary dipole attractions between nonpolar molecules
Term
Dipole-Dipole Forces
Example
HCl, CO, polar molecules
Definition
Attractions between polar molecules
Term
Hydrogen Bonding
Example
H2O, NH3, HF
Definition
Strong dipole force with H bonded to F, O, or N
Term
Ion-Dipole Forces
Example
NaCl dissolved in water
Definition
Attraction between ion and polar molecule
Diagrams To Know
- IMFA interaction diagrams
- Hydrogen bonding in water
- Ion-dipole interactions
Section Title
Chemical Nomenclature
Important Facts
- Greek prefixes: mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca-
- Drop 'mono-' prefix on first element
- Polyatomic ions ending in -ate make -ic acids
- Polyatomic ions ending in -ite make -ous acids
- Binary acids: hydro- + root + -ic + acid
- Oxyanions: per-ic > -ic > -ous > hypo-ous
Key Definitions
Term
Binary Ionic Compound
Example
NaCl = sodium chloride
Definition
Metal + nonmetal, name metal first then nonmetal with -ide
Term
Binary Covalent Compound
Example
CO2 = carbon dioxide
Definition
Two nonmetals, use Greek prefixes
Term
Polyatomic Ion
Example
SO42- = sulfate
Definition
Group of atoms with overall charge
Term
Transition Metal Compound
Example
FeCl3 = iron(III) chloride
Definition
Use Roman numerals for metal charge
Diagrams To Know
- Flowchart for naming compounds
- Polyatomic ion structures
Common Values
Value
OH-
Symbol
OH-
Quantity
Hydroxide
Value
SO42-
Symbol
SO42-
Quantity
Sulfate
Value
NO3-
Symbol
NO3-
Quantity
Nitrate
Value
CO32-
Symbol
CO32-
Quantity
Carbonate
Value
PO43-
Symbol
PO43-
Quantity
Phosphate
Value
NH4+
Symbol
NH4+
Quantity
Ammonium
Value
CH3COO-
Symbol
CH3COO-
Quantity
Acetate
Value
MnO4-
Symbol
MnO4-
Quantity
Permanganate
Section Title
Common Polyatomic Ions
Must Remember
- Periodic trends: atomic radius decreases across period, increases down group
- Electronegativity difference > 1.7 = ionic, 0.4-1.7 = polar covalent, < 0.4 = nonpolar
- IMFA strength order: Ion-Dipole > H-bonding > Dipole-Dipole > London Dispersion
- Formal Charge = Valence electrons - Nonbonding electrons - Bonding electrons/2
- Water has bent geometry (104.5°) due to 2 lone pairs on oxygen
- Hydrogen bonding only occurs with H-F, H-O, H-N bonds
- Group charges: 1A(+1), 2A(+2), 15A(-3), 16A(-2), 17A(-1)
- Common polyatomic ions: SO42-(sulfate), NO3-(nitrate), OH-(hydroxide), NH4+(ammonium)
- Binary acids: hydro- + root + -ic acid (HCl = hydrochloric acid)
- Transition metals need Roman numerals to show charge (Fe3+ = iron(III))
Last Minute Tips
- For Lewis structures, always check formal charges - closest to zero is best
- Remember molecular geometry depends on TOTAL electron pairs (bonding + lone pairs)
- When naming compounds, identify if ionic or covalent first, then apply rules
- Hydrogen bonding requires H attached to F, O, or N - memorize FON
- For periodic trends, think of nuclear charge increasing across periods
Comparison Tables
Rows
Values
- Transfer
- Sharing
- Sea of electrons
Property
Electron behavior
Values
- Metal + Nonmetal
- Nonmetal + Nonmetal
- Metal + Metal
Property
Between
Values
- When dissolved/molten
- Poor
- Excellent
Property
Conductivity
Values
- Often soluble in water
- Varies
- Insoluble
Property
Solubility
Values
- Generally high
- Varies widely
- Generally high
Property
Melting point
Columns
- Property
- Ionic
- Covalent
- Metallic
Table Title
Ionic vs Covalent vs Metallic Bonding
Rows
Values
- Weakest
- All molecules
- CH4, He
Property
London Dispersion
Values
- Moderate
- Polar molecules
- HCl, CO
Property
Dipole-Dipole
Values
- Strong
- H-F, H-O, H-N
- H2O, NH3
Property
Hydrogen Bonding
Values
- Ion + polar solvent
- NaCl in water
Property
Ion-Dipole
Columns
- Force Type
- Strength
- Found in
- Example
Table Title
IMFA Strength Comparison
Ready to practise for the UPCAT 2026?
Super Tutor's AI review plan adapts to your weak areas and builds a weekly practice schedule around your target UPCAT exam date.