Module 1: Atoms and The Periodic Table

Atoms

Smallest unit of matter that retains the identity of an element

Elements

A pure substance made of only one type of atom

Molecules

Two or more atoms chemically bonded together

Compounds

A substance made of two or more different elements chemically bounded

Pure Substances

Matter with a fixed composition and uniform properties (elements + compounds)

Mixtures

Combination of 2 or more substances that are physically mixed but not chemically bonded

Homogeneous Mixture

A mixture with uniform composition throughout (salt water)

Heterogeneous Mixture

A mixture with visibly different parts or phases (salad, sand + iron)

Structure of an atom

Atoms gave a nucleus (protons + neutrons) and an electron cloud (electrons orbiting the nucleus)

Proton

Positively charged particle in the nucleus

Neutron

Negatively charged particle found in the electron cloud

Electron

Negatively charged particle found in the electron cloud

Atomic number

number of protons in an atom; identifies the element

Mass number

Number of proteins + neutrons

charge of an ion

protons — electrons (positive if more protons, negative is more electrons)

Periodic table: groups

vertical columns; elements in a group have similar chemical properties

Periodic table: periods

horizontal rows: properties chnage gredually across a period

Metals

elements are shiny, conductive, malleable, ductile; tend to lose electrons

Nonmetals

dull, poor, conductors, brittle (if solid); tend to gain electrons

metalloids

have properties of both metals and nonmetals; semiconductors

rare earth elements

Set of 17 elements (lanthanides + scandium + yttrium) used in electronics, magnets, batteries, military tech. Hard to separate; not “rare” in amount, just hard to process.

Uses of rare earth elements

smartphones, EV motors, wind turbines

UN sustainable development goals (SDGs)

17 global goals addressing poverty, climate, clean energy, responsible consumption, etc.

SDGs & mining

Mining must balance resource needs (Goal 9: Industry/Innovation) with environmental protection (Goal 13: Climate Action) and responsible production (Goal 12). Policies emphasize reducing pollution, improving worker safety, recycling materials, and ensuring ethical sourcing.