2.6 Subatomic Particles: Protons, Neutrons, and Electrons in Atoms

atomic mass unit (amu)

a unit used to express the masses of atoms and subatomic particles, defined as 1/12 the mass of a carbon atom containing 6 protons and 6 neutrons

protons and neutrons

Which two subatomic particles have a mass of approximately 1 amu?

electron

Which subatomic particle has an almost negligible mass?

equal, opposite

Charged subatomic particles are _____ (equal/opposite) in magnitude and ________ (equal/opposite) in sign.

equalize

When matter does acquire charge imbalances, these imbalances usually ________ quickly, often in dramatic ways.

atomic number (Z)

the number of protons in an atom; defines the element

chemical symbol (X)

one- or two-letter abbreviation unique to each element listed directly below its atomic number on the periodic table

isotope

atoms with the same number of protons but different numbers of neutrons and consequently different masses

the same

Among an element’s isotopes, the size of the atoms is __________ (the same/different) because the nucleus where neutrons are located is minuscule compared to the atom itself.

natural abundance

the relative percentage of a particular isotope in a naturally occurring sample with respect to other isotopes of the same element

mass number (A)

number of protons (p) + number of neutrons (n)

^A_ZX

isotope notation using mass number, atomic number, and chemical symbol

X-A

isotope notation using chemical symbol/name and mass number

ions

an atom or molecule with a net charge caused by the loss or gain of electrons

cations

positively charged ions

anions

negatively charged ions

differently than

Ions behave ______________ (similarly to/differently than) their corresponding atoms.