Chemical Context of Life - Chapter 2.1

Vocabulary flashcards covering fundamental chemistry concepts, atomic structure, isotopes, and chemical bonding from Chapter 2.1.

Proton

A positively charged subatomic particle located in the nucleus of an atom, with a mass of $1.7 \times 10^{-24}\,g$ ($1\,\text{Da}$).

Neutron

An uncharged subatomic particle located in the nucleus of an atom, with a mass of $1.7 \times 10^{-24}\,g$ ($1\,\text{Da}$).

Electron

A negatively charged subatomic particle located outside the nucleus in electron orbitals, with a mass of $9.1 \times 10^{-28}\,g$ (about 1/2000 the mass of a proton or neutron).

Atomic Number

The number of protons in an atom, which dictates its chemical properties.

Mass Number

The total number of protons plus neutrons in an atom's nucleus.

Isotope

Atoms of the same element that share the same chemical reactivity and proton count, but differ in their number of neutrons.

Radioactive Isotope

An unstable isotope that decays spontaneously over time, giving off particles and energy.

Half-life

The amount of time required for half of the original amount of a radioactive isotope substance to decay (e.g., 5,700 years for Carbon-14).

Valence Shell

The outermost energy level of an atom containing electrons that determine the energetic stability and bonding behavior of the atom.

Octet Rule

The principle stating that elements achieve their highest stability when their outermost electron shell is fully filled.

Molecule

A chemical structure formed when two or more atoms chemically bond with each other.

Covalent Bond

A chemical bond formed when two atoms share pairs of electrons.

Nonpolar Covalent Bond

A type of covalent bond in which electrons are shared equally between two atoms.

Polar Covalent Bond

A type of covalent bond where electrons are shared unequally between atoms due to differences in electronegativity, creating partial positive (\delta+) and partial negative (\delta-) charges.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Ionic Bond

A chemical bond formed between oppositely charged ions created when atoms transfer electrons.

Hydrogen Bond

A weak chemical interaction between a hydrogen atom covalently bonded to an electronegative atom (such as oxygen or nitrogen) and another electronegative atom.

van der Waals Interactions

Weak chemical interactions caused by transient regions of polarity that become attractive and can induce polarity in neighboring molecules.