chem test

Bohr-Rutherford Diagrams

Diagrams showing the arrangement of electrons around the nucleus of an atom with circles for electron shells.

Atomic Number (Z)

The number of protons in the nucleus of an atom, represented in standard atomic notation.

Mass Number (A)

The total number of protons and neutrons in the nucleus of an atom, used in standard atomic notation.

Electronegativity

The tendency of an atom to attract electrons, which increases across a period and decreases down a group.

Ionization Energy

The energy required to remove an electron from an atom; it increases across a period and decreases down a group.

Periodic Trends

Patterns in the periodic table, such as atomic radius, ionization energy, and electronegativity.

Covalent Bonds

Chemical bonds formed when atoms share electrons, typically between non-metals.

Ionic Bonds

Chemical bonds formed when atoms transfer electrons, resulting in the formation of ions, typically between metals and non-metals.

Pure Substances

Materials made of only one type of particle, including elements and compounds.

Homogeneous Mixtures

Mixtures that have a uniform composition, such as salt water.

Heterogeneous Mixtures

Mixtures that do not have a uniform composition, like salad or sand in water.

Physical Properties

Characteristics that can be observed without changing the substance, such as color and density.

Chemical Properties

Attributes that describe a substance’s ability to undergo chemical changes, like flammability.

Physical Changes

Changes that affect one or more physical properties of a substance without altering its chemical composition.

Chemical Changes

Processes that result in the formation of new substances with different properties, such as rusting.

Oxygen Test

A procedure where a glowing splint is placed in gas; if it reignites, oxygen is present.

Hydrogen Test

A procedure where a burning splint is placed near gas; a 'pop' sound indicates hydrogen is present.

Carbon Dioxide Test

A test where bubbling gas through limewater turns it cloudy, indicating the presence of carbon dioxide.

Valency

The combining power of an atom, indicating how many bonds it can form; e.g., Oxygen has a valency of 2.

Molecular Geometry

The 3D arrangement of atoms in a molecule; examples include linear, bent, and tetrahedral.

Standard Atomic Notation

A format for representing atoms, written as ext{^{A}_{Z}X}, where A is mass number, Z is atomic number, and X is the element symbol.