Atom
The smallest unit of matter that retains the properties of an element.
Recognize the subatomic particles (protons, neutrons, electrons) + theri location
Protons (p⁺): Positively charged particles - located in the nucleus.
Neutrons (n⁰): Neutral particles (no charge) - located in the nucleus.
Electrons (e⁻): Negatively charged particles that orbit the nucleus in energy levels. - located in electron cloud.
Difference between atoms, isotopes, and ions
Atom: Neutral particle; equal number of protons and electrons.
Isotope: Atoms of the same element (same # of protons) with different # of neutrons.
Ion: Atom that has gained or lost electrons, giving it a net charge.
Identify the charge of an ion based on subatomic particles
If there are more electrons than protons → the ion is negative (anion).
If there are fewer electrons than protons → the ion is positive (cation).
Families/ groups
columns: similar chemical properties and the same number of valence electrons, and therefore ionic charge.
Periods
Rows - same number of energy levels in their atoms.
group names
1 - Alkali Metals
1 - Alkaline Earth metals
2nd last - hallogens
last - noble gases
Representative
everything but transition - noble gases sometimes representative
Why does an electron stay in an atom?
The positive protons in the nucleus attract the negative electrons (opposite charges attract)
Shorter distance between particles = stronger attraction
Therefore, core electrons have a stronger attraction to the nucleus!
Molecular Compounds
Covalent Compounds
Electronegativity
An atom’s ability to attract to the electrons of another atom
Atoms’ differences in electronegativity determine what type of bond they will form.
Differences in electronegativity per type of bond
zero/ almost zero - nonpolar covalent (Atoms share electrons evenly)
small - polar covalent (Atoms share electrons unevenly)
large - ionic
law of composition and multiple proportions
Nonmetals can come together in multiple proportions, so prefixes are needed in covalent molecule names to indicate HOW MANY atoms.
