What is an atom?
The smallest unit of matter that makes up everything.
What are the three main parts of an atom?
Protons, neutrons, and electrons.
Where are protons and neutrons found?
In the nucleus (center of the atom).
Where are electrons found?
In the electron cloud around the nucleus.
What charge does a proton have?
Positive (+).
What charge does an electron have?
Negative (–).
What charge does a neutron have?
(neutral).
Atomic mass
The total mass of the nucleus, reflecting the combined mass of protons and nutrons
atomic number
This tells how many protons are in the nucleus of the atom. (remember that the number of protons identifies the element)
stability/full outer shell
atoms reach a lower-energy, more stable arrangement when their outer shell is completel
isotopes
atoms of the same element that have different masses (because they have different numbers of protons)
periodic table trends
Elements that share the same group have the same number of valence electrons; those in the same period have the same number of electrons shells
