Molecular Biology - Atoms and Elements

Vocabulary flashcards for key terms related to atoms, elements, and chemical bonds.

Proton

Subatomic particle with a positive charge located in the nucleus.

Neutron

Subatomic particle with no charge located in the nucleus.

Electron

Subatomic particle with a negative charge orbiting the nucleus.

Nucleus

The central part of an atom, containing protons and neutrons.

Dalton (or amu)

Unit of measurement for atomic mass, approximately equal to the mass of a proton or neutron.

Isotopes

Atoms with the same number of protons but different numbers of neutrons; affects mass but behaves identically in chemical reactions.

Atomic Mass

The average mass of all isotopes of an element.

Covalent Bond

Atoms sharing one or more pairs of valence electrons.

Ionic Bond

A bond resulting from the attraction between oppositely charged ions.

Electronegativity

The measure of the ability of an atom to attract electrons in a chemical bond.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Hydrogen Bond

Weak bond formed by the attraction between a slightly positive hydrogen atom and a slightly negative atom in a polar covalent bond.

Van der Waals Interactions (VDW)

Weak attractions between molecules or parts of molecules resulting from transient local partial charges.

Valence Shell

The outermost electron shell of an atom.

Valence Electrons

Electrons in the outermost electron shell; determines the bonding capacity of an atom.

Valence

The bonding capacity of a given atom, typically determined by the number of unpaired electrons in the outer shell.

Radioactive Decay

Where the nucleus decays spontaneously, giving off particles and energy to reach a more stable state.