Chemistry In Biology (December 18 2025)

Has custom hints!

What is atomic mass?

The total weight of both protons and neutrons in an element’s nucleus.

What is atomic number?

The number of protons in the nucleus of an atom, and also the number of electrons in a neutral atom.

How do you calculate the number of neutrons in an atom?

Subtract the atomic number from the atomic mass.

How do you calculate the number of electrons in a neutral atom?

Take the atomic number.

What is an electron shell?

A specific energy level around the nucleus where electrons reside.

What is the duet rule?

The first electron shell around the nucleus can contain a max of 2 electrons.

What is the octet rule?

All electrons shells after the first can contain a max of 8 electrons.

What is bonding?

Bonding is the force of attraction that holds atoms together, forming compounds. The main types are ionic, covalent, and metallic.

What are valence electrons?

The electrons in an atoms outer shell, they are crucial for determining an atom’s reactivity and chemical properties.

What is an ionic bond?

One atom transfers valence electrons to the other, creating oppositely charged ions that stick together due to electrostatic force.

What is a covalent bond?

Two atoms share valence electrons, forming a stable outer shell.

What is a metallic bond? (Not on test)

The strong attraction between positive metal ions and a "sea" of freely moving valence electrons that are shared among all the atoms, holding the metal structure together.

What is an example of an ionic bond?

Sodium Chloride (NaCl), Magnesium Oxide (MgO), Calcium Chloride (CaCl₂), Potassium Fluoride (KF), etc.

What is an example of a covalent bond?

Water (H₂O), Methane (CH₄), Ammonia (NH₃), Oxygen (O₂), Carbon Dioxide (CO₂), etc.

What is an ion?

An atom that is positively or negatively charged, due to an imbalance in protons and electrons.

What charge does a proton have?

Positive.

What charge does a neutron have?

None/Neutral.

What charge does an electron have?

Negative.

What is a cation?

A positively charged ion. Has more protons than electrons.

What is an anion?

A negatively charged ion. Has more electrons than protons.

What is electronegativity?

The measure of how strongly an atom pulls valence electrons. Atoms with higher electronegativity are found in the upper right side of the periodic table.

What is a polar bond?

A chemical bond where electrons are shared unevenly between atoms, creating a slight negative charge near one atom and a slight positive charge near the other. This is denoted by either ⁺ or ^- .

What is a non polar bond?

A covalent bond where atoms are shared equally. This usually occurs due to atoms having close electronegativities.

What is an isotope?

A type of element with the same number of protons but a different number of neutrons. Carbon 12 and Carbon 14 are examples.