RAD PROD - Atom Structure

atom

smallest unit of an element that retains the chemical properties of that element

electrons

atoms are composed of a dense, central nucleus and a surrounding cloud of ——-

protons (positively charged particles) and neutrons (electrically neutral particles)

The nucleus contains ——-

electron shells / Electrons (negatively charged particles)

orbit the nucleus in specific energy levels

nucleus

is the positively charged center of an atom, containing most of the atom's mass

nucleons

It is composed of protons and neutrons, collectively called ——

strong force

The nucleus is held together by the ——, one of the four fundamental forces in nature

The number of protons in the nucleus

it defines the element to which the atom belongs (atomic number)

Electrons

they are negatively charged subatomic particles that orbit the nucleus

Electrons

They are much smaller and lighter than protons and neutrons

Electrons

— occupy specific energy levels or shells around the nucleus, with each shell holding a maximum number of electrons

valence electrons

— determines an atom's chemical properties and how it interacts with other atoms

valence electrons

The arrangement of electrons in the outermost shell

Atomic weight / atomic mass

is the mass of an atom, typically expressed in atomic mass units (amu)

One amu

is defined as one-twelfth the mass of a carbon-12 atom

atomic weight

is determined by the average mass of all its naturally occurring isotopes, taking into account their relative abundances

Atomic weight

is not always a whole number due to the presence of isotopes with different numbers of neutrons

Electrons

occupy specific energy levels or shells around the nucleus

Electron Shells

These shells are designated with letters: K, L, M, N, O, P, and Q, with the K-shell being closest to the nucleus

K shell

can hold 2 electrons

L shell

can hold 8 electrons

M shell

can hold 18 shells

N shell

can hold 32 electrons

O shell

can hold 50 electrons

Electrons in shells further from the nucleus

have higher energy levels and are less tightly bound to the nucleus

Electron binding energy

is the energy required to remove an electron from an atom, overcoming the electrostatic attraction between the electron and the positively charged nucleus

Electron Binding Energy

is measured in electron volts (eV) or kiloelectron volts (keV)

Electrons closer to the nucleus

have higher binding energies than those in outer shells because they are more strongly attracted to the nucleus

K-shell electrons

have the highest binding energies within an atom

Electron Binding energy

increases with the atomic number (Z) of the element

Atomic Number (Z)

The number of protons in an atom's nucleus. It determines the element to which an atom belongs

Atomic Mass Unit (AMU)

A unit of mass equal to one-twelfth the mass of a carbon-12 atom. It's used to express the mass of atoms and subatomic particles