CHEMISTRY

Physical Properties

Properties you can find out without changing what the substance is.

Examples of Physical Properties

Color and smell.

Chemical Properties

Properties you can only find out by changing the substance into something new.

Examples of Chemical Properties

Flammability and toxicity.

Physical Change

A change that can be reversed, such as melting or freezing.

Chemical Change

A permanent change, such as frying an egg or burning wood.

Three States of Matter

Solid, liquid, gas.

Solid Behavior

Particles are tightly packed and vibrating.

Liquid Behavior

Particles are further apart and able to flow past each other.

Gas Behavior

Particles are very far apart and fly around.

Subatomic Particles

Protons, neutrons, and electrons.

Proton Charge and Size

Positive charge, size of 1.

Neutron Charge and Size

Neutral charge, size of 1.

Electron Charge and Size

Negative charge, size 1/1838 of a proton or neutron.

Location of Protons and Neutrons

In the nucleus of an atom.

Location of Electrons

Orbit around the nucleus.

Difference between Element and Compound

An element is a specific type of atom, and a compound is a combination of two or more different elements.

Difference between Compound and Mixture

A compound is a chemical combination; a mixture consists of different particles in the same space.

Examples of Elements

Iron (Fe) and Magnesium (Mg).

Examples of Compounds

Water (H2O) and table salt (NaCl).

Examples of Mixtures

Tea and milk.

Arrangement of Periodic Table

Organized by atomic number, which is the number of protons.

Father of Modern Periodic Table

Dmitri Mendeleev.

Rows of Periodic Table

Called periods; elements in a period have the same number of orbitals.

Columns of Periodic Table

Called groups; elements in a group have the same number of valence electrons.

Atomic Number

The number of protons that determines the type of element.

Atomic Mass

Sum of protons and neutrons.

Isotope

Different versions of the same element with different masses.

Anion vs Cation

An anion gains an electron, a cation loses an electron.

Metals and Cations

Metals usually become cations (e.g., Mg2+).

Non-Metals and Anions

Non-metals usually become anions (e.g., O2-).

Ionic Bonds

Formed between metals and non-metals; involve electron transfer.

Covalent Bonds

Formed between non-metals; involve electron sharing.

Rutherford’s Experiment

The Gold Foil Experiment, which revealed the positive nucleus of the atom.

Combustion Reaction

When something burns in the presence of oxygen.

Reactants of a Chemical Equation

The starting materials in a chemical reaction.

Products of a Chemical Equation

The substances formed from a chemical reaction.