Unit Topic: The Atom

Plum Pudding Model

Proposes that the atom has no nucleus, mass is spread throughout, and negative electrons are embedded in a positive matrix.

Nuclear Model

Proposes that the atom contains a nucleus with concentrated mass, mostly empty space, and electrons orbiting the nucleus.

Bohr Model

Suggests electrons travel in fixed circular paths around the nucleus at set distances.

Electron Cloud Model

Poses that electrons exist in probabilistic clouds rather than fixed orbits, making their position and momentum uncertain.

Electron Cloud

The region surrounding the nucleus where electrons are located, which is broken into shells with varying energy levels.

Electromagnetic Force

The attractive force that holds the atom together, arising from the interaction between the positively charged nucleus and the negatively charged electron cloud.

Strong Nuclear Force

The force that holds protons and neutrons together in the nucleus despite the repulsion between protons.

Groups in the Periodic Table

Vertical columns in the periodic table where elements share similar chemical properties due to having the same number of valence electrons.

Periods in the Periodic Table

Horizontal rows in the periodic table where elements have the same number of electron shells, but their properties change across the row.

Metals

Elements that are typically shiny, conductive, malleable, and found on the left side of the periodic table.

Nonmetals

Elements that are dull, poorly conductive, and can exist in solid, liquid, or gas forms at room temperature, found on the right side of the periodic table.

Metalloids

Elements that have properties of both metals and nonmetals, found along the diagonal line on the periodic table.

Hyphen Notation

A way to represent isotopes, such as Hydrogen-1, indicating the mass number.

Nuclear Notation

A way to represent isotopes using superscripts, like ( ^{1}H ), indicating the mass number.

Electrically Neutral Atoms

Atoms that have equal numbers of protons and electrons, resulting in no net charge.

Cation

A positively charged ion formed by the loss of electrons.

Anion

A negatively charged ion formed by the gain of electrons.