Chemistry: Elements, Ions, and Atomic Structure Basics

Symbol for Hydrogen?

H

Name of element with symbol H?

Hydrogen

Symbol for Helium?

He

Name of element with symbol He?

Helium

Symbol for Lithium?

Li

Name of element with symbol Li?

Lithium

Symbol for Beryllium?

Be

Name of element with symbol Be?

Beryllium

Symbol for Boron?

B

Name of element with symbol B?

Boron

Symbol for Carbon?

C

Name of element with symbol C?

Carbon

Symbol for Nitrogen?

N

Name of element with symbol N?

Nitrogen

Symbol for Oxygen?

O

Name of element with symbol O?

Oxygen

Symbol for Fluorine?

F

Name of element with symbol F?

Fluorine

Symbol for Neon?

Ne

Name of element with symbol Ne?

Neon

Formula for Ammonium?

NH4⁺

Name of polyatomic ion NH4⁺?

Ammonium

Formula for Hydroxide?

OH⁻

Name of polyatomic ion OH⁻?

Hydroxide

Formula for Nitrate?

NO3⁻

Name of polyatomic ion NO3⁻?

Nitrate

Formula for Nitrite?

NO2⁻

Name of polyatomic ion NO2⁻?

Nitrite

Formula for Sulfate?

SO4²⁻

Name of polyatomic ion SO4²⁻?

Sulfate

Formula for Sulfite?

SO3²⁻

Name of polyatomic ion SO3²⁻?

Sulfite

Formula for Carbonate?

CO3²⁻

Name of polyatomic ion CO3²⁻?

Carbonate

Formula for Bicarbonate (hydrogen carbonate)?

HCO3⁻

Name of polyatomic ion HCO3⁻?

Bicarbonate (hydrogen carbonate)

Formula for Phosphate?

PO4³⁻

Name of polyatomic ion PO4³⁻?

Phosphate

Formula for Hydrogen phosphate?

HPO4²⁻

Name of polyatomic ion HPO4²⁻?

Hydrogen phosphate

Formula for Dihydrogen phosphate?

H2PO4⁻

Name of polyatomic ion H2PO4⁻?

Dihydrogen phosphate

Formula for Cyanide?

CN⁻

Dihydrogen phosphate

Formula for Cyanide

CN⁻

Name of polyatomic ion CN⁻

Cyanide

Formula for Acetate

C2H3O2⁻

Name of polyatomic ion C2H3O2⁻

Acetate

Formula for Chlorate

ClO3⁻

Name of polyatomic ion ClO3⁻

Chlorate

Formula for Chlorite

ClO2⁻

Name of polyatomic ion ClO2⁻

Chlorite

Formula for Hypochlorite

ClO⁻

Name of polyatomic ion ClO⁻

Hypochlorite

Formula for Perchlorate

ClO4⁻

Name of polyatomic ion ClO4⁻

Perchlorate

Formula for Chromate

CrO4²⁻

Name of polyatomic ion CrO4²⁻

Chromate

Formula for Dichromate

Cr2O7²⁻

Name of polyatomic ion Cr2O7²⁻

Dichromate

Formula for Permanganate

MnO4⁻

Name of polyatomic ion MnO4⁻

Permanganate

What are the three main subatomic particles?

Proton (+, nucleus), Neutron (0, nucleus), Electron (−, outside nucleus)

What does the atomic number (Z) represent?

Number of protons (and electrons in neutral atom)

What does the mass number (A) represent?

Protons + neutrons

What are isotopes?

Atoms of the same element with different numbers of neutrons

How are isotopes written?

Element name-mass number (Carbon-14) or nuclear symbol (¹⁴₆C)

What are alkali metals?

Group 1: Li, Na, K, Rb, Cs, Fr

What are alkaline earth metals?

Group 2: Be, Mg, Ca, Sr, Ba, Ra

What are halogens?

Group 17: F, Cl, Br, I, At, Ts

What are noble gases?

Group 18: He, Ne, Ar, Kr, Xe, Rn, Og

What is a cation?

A positively charged ion (lost electrons)

What is an anion?

A negatively charged ion (gained electrons)

What charge do alkali metals typically form?

1

What charge do halogens typically form?

−1

Formula and charge for sulfate?

SO₄²⁻

Name NaCl.

Sodium chloride (ionic compound)

Name CO₂.

Carbon dioxide (molecular compound)

Name N₂O₅.

Dinitrogen pentoxide

What is Avogadro's number?

6.022 × 10²³

What is 1 mole of H₂O molecules?

6.022 × 10²³ molecules of H₂O

How many grams are in 1 mole of carbon?

12.01 g

Convert 2.5 mol NaCl to grams.

(M = 58.44 g/mol) ≈146 g

Convert 12 g of C to moles.

(M = 12 g/mol) 1 mol

What is percent composition?

The percent by mass of each element in a compound

What is an empirical formula?

The simplest whole-number ratio of atoms in a compound

What is a molecular formula?

The actual number of atoms in a compound (may be a multiple of empirical formula)

How can matter be classified?

Matter is classified as pure substances (elements, compounds) or mixtures (homogeneous, heterogeneous)

What is a homogeneous mixture?

A mixture with uniform composition throughout (e.g., salt water, air)

What is a heterogeneous mixture?

A mixture with visibly different components (e.g., salad, sand in water)

What is an element?

A substance made of only one type of atom (e.g., O₂, Fe)

What is a compound?

A substance made of two or more different elements chemically bonded (e.g., H₂O, NaCl)

Give an example of a physical property.

Color, density, melting point, boiling point

What is density?

Density = mass ÷ volume

What is a physical change?

A change that does not alter the identity of a substance (e.g., melting ice)

What is a chemical change?

A change that results in new substances (e.g., burning wood, rusting)

What are SI base units for length, mass, volume, time?

Length = meter (m), Mass = kilogram (kg), Volume = liter (L), Time = second (s)

Order these prefixes from largest to smallest: giga, mega, kilo, deci, centi, milli, micro, nano, pico.

G, M, k, d, c, m, μ, n, p

Convert 25°C to Kelvin.

25 + 273 = 298 K

What is dimensional analysis?

A method of converting units using conversion factors to cancel unwanted units