Chemistry: CORRECT study guide

What do chemical symbols represent?

represent elements and are based on their Latin or English names (e.g., H for Hydrogen, Fe for Iron).

What does the atomic number indicate?

indicates the number of protons in an atom.

What does the mass number represent?

the total number of protons and neutrons in an atom.

What is an isotope?

Isotopes are atoms of the same element with different numbers of neutrons.

How do you determine the number of neutrons in an atom?

Subtract the atomic number from the mass number:

Neutrons = Mass Number - Atomic Number.

How do you know what an average atomic mass is?

The element's isotopes.

How is average atomic mass calculated?

multiply the mass of each isotope of an element by its natural abundance (as a decimal), then add up the results for all isotopes

Where are alkali metals located?

Group 1 (except Hydrogen).

Where are alkaline earth metals located?

Group 2.

Where are transition metals located?

Groups 3-12.

Where are inner transition elements located?

The two rows at the bottom (lanthanides & actinides).

Where are halogens located?

Group 17.

Where are noble gases located?

Group 18.

Where are metals located?

Left & center of the periodic table.

where are nonmetals located?

Right side (except Hydrogen).

where are metalliods located

Along the staircase (B, Si, Ge, As, Sb, Te, Po).

What are periods on the periodic table?

Periods: Horizontal rows.

What are groups on the periodic table?

Groups: Vertical columns (elements in a group have similar properties).

What are the properties of metals?

Good conductors, malleable, ductile, shiny, solid at room temperature (except Hg).

What are the properties of nonmetals?

Poor conductors, brittle, dull, can be solid, liquid, or gas at room temperature.

What are the properties of metalloids?

Have properties of both metals and nonmetals; semi-conductors.

What is the octet rule?

Atoms gain, lose, or share electrons to have eight valence electrons (like noble gases).

What is an ion?

An atom or group of atoms with a charge due to gaining or losing electrons.

How is charge indicated?

With a superscript, e.g., Na⁺, Cl⁻, Mg²⁺.

How is charge for cations and anions determined?

Metals lose electrons → Positive charge (cation).

Nonmetals gain electrons → Negative charge (anion).

How do you determine the number of electrons in an ion?

Electrons = Atomic Number - Charge (for cations) /

Electrons = Atomic Number + Charge (for anions).

What is the difference between molecular and ionic compounds?

Molecular compounds: Formed by covalent bonds (nonmetals). 2 nonmetals

Ionic compounds: Formed by transfer of electrons between metals and nonmetals. (metal and nonmetal)

What is the difference between molecular and empirical formulas?

Molecular formula: Shows the actual number of atoms (e.g., C₂H₆).

Empirical formula: Simplest whole-number ratio (e.g., CH₃ for C₂H₆).

What is the difference between cations and anions?

Cations: Positively charged ions (lose electrons).

Anions: Negatively charged ions (gain electrons).

What is the difference between monatomic and polyatomic ions?

Monatomic ion: Single atom with a charge (e.g., Na⁺, Cl⁻).

Polyatomic ion: Group of atoms with a charge (e.g., NO₃⁻, SO₄²⁻).

What is the difference between diatomic and polyatomic molecules?

Diatomic molecules: Two atoms of the same element (e.g., O₂, N₂).

Polyatomic molecules: More than two atoms (e.g., H₂O, CO₂).

What is the difference between binary and ternary compounds?

Binary compounds: Two different elements (e.g., NaCl, CO₂).

Ternary compounds: Three or more elements (e.g., NaNO₃, CaCO₃).