Chapter 2 - Chemical Basis of Life

Vocabulary flashcards covering foundational chemistry concepts from Chapter 2, including matter, subatomic particles, atomic numbers, isotopes, and chemical bonds.

Matter

Anything that occupies space and has mass.

Elements

Substances that cannot be broken down into simpler substances by ordinary chemical reactions. There are 109 total elements (92 natural and 17 'artificial').

Atom

The building blocks of elements.

Neutron

A subatomic particle found within the nucleus that has no electrical charge and a mass of $1\,\text{amu}$.

Proton

A subatomic particle found within the nucleus that has a $+1$ electrical charge and a mass of $1\,\text{amu}$.

Electron

A subatomic particle with a $-1$ electrical charge and a mass of $0\,\text{amu}$.

Atomic Number ($Z$)

The number of protons (\text{#p}) in an atom, which is also equal to the number of electrons (\text{#e}).

Mass Number

The sum of the number of protons and neutrons (\text{#p} + \text{#n}) in an atom.

Isotopes

Atoms with the same number of protons and electrons but a different number of neutrons (e.g., $^{1}\text{H}$, $^{2}\text{H}$, $^{3}\text{H}$).

Radioactive Isotopes

Atoms with unstable nuclei that undergo decay, used in clinical imaging techniques and $^{14}\text{C}$ dating of biological materials.

Molecules

Two or more atoms joined together by chemical bonds.

Chemical Bonds

Interactions where atoms in a molecule transfer or share electrons in their outermost shell.

Ionic Bonds

Chemical bonds in which opposite-charged ions are attracted to one another (e.g., $\text{NaCl}$).

Ions

Atoms that have gained or lost an electron.

Cation

An ion formed when an atom loses an electron, becoming positively charged; typical of metals.

Anion

An ion formed when an atom gains an electron, becoming negatively charged; typical of nonmetals.

Covalent Bonds

Chemical bonds formed by the sharing of electron pairs between atoms in a molecule.

Nonpolar Covalent Bond

A covalent bond involving the equal sharing of electrons between atoms (e.g., $\text{H}_2$, $\text{O}_2$, $\text{N}_2$).

Polar Covalent Bond

A covalent bond involving the unequal sharing of electrons, resulting in a molecule with positive and negative regions (e.g., $\text{H}_2\text{O}$).