Characteristics of Atoms
History of the Atom
Properties of Atoms
How Atoms Bond
100

What is a proton?

This subatomic particle carries a positive charge and is found in the nucleus.

100

Who is Democritus?

This ancient Greek philosopher first proposed that all matter is made of tiny, indivisible particles called "atomos."

100

What is the nucleus?

The mass of an atom is mostly concentrated in this part.

100

What is a covalent bond?

In this type of bond, atoms share electrons.

200

What are isotopes?

Atoms of the same element with different numbers of neutrons are called this.

200

Who is John Dalton?

He developed the first scientific atomic theory in the early 1800s, stating that atoms are solid spheres.

200

What is atomic mass?

This is the term for the weighted average mass of all isotopes of an element.

200

What is an ionic bond?

In this type of bond, atoms transfer electrons to form oppositely charged ions.

300

What is the atomic number?

This number tells you the number of protons in an atom.

300

Who is J.J. Thomson?

This scientist discovered the electron using a cathode ray tube.

300

What is electronegativity?

The ability of an atom to attract electrons in a chemical bond is called this.

300

What is a metallic bond?

This is the name for the attraction between positively charged metal ions and the electrons around them.

400

What is the electron cloud?

The cloud-like region around the nucleus where electrons are likely found is called this.


400

Who is Ernest Rutherford?

His gold foil experiment led to the discovery of the atomic nucleus.

400

What is negative?

An atom with more electrons than protons has this type of overall charge.

400

What is the octet rule?

This rule states that atoms tend to bond in a way that each atom has eight electrons in its valence shell.

500

What is zero?

The overall charge of a neutral atom is this?

500

Who is Niels Bohr?

This Danish scientist proposed that electrons orbit the nucleus in specific energy levels.

500

What are noble gases?

These are atoms with a full outer energy level, making them very stable.

500

What is a polar molecule?

A molecule with uneven sharing of electrons, leading to a slightly positive and negative side, is called this.