Atoms and ElementsAtoms and Elements

Subatomic ParticlesSubatomic Particles AtomAtom-- Smallest particle of an element.Smallest particle of an element. Subatomic ParticlesSubatomic Particles- Atoms are composed of - Atoms are composed of

protons, neutrons, and electrons. protons, neutrons, and electrons. NucleusNucleus- Small dense positively charged center - Small dense positively charged center

of an atomof an atom. . ProtonProton- Subatomic particle that has a positive - Subatomic particle that has a positive

charge and is found in the nucleus of an atomcharge and is found in the nucleus of an atom.. ElectronElectron- negatively charged subatomic particle - negatively charged subatomic particle

found in an area outside the nucleus of an atom.found in an area outside the nucleus of an atom. NeutronNeutron- Subatomic particle with no electric - Subatomic particle with no electric

charge that is found in the nucleus of an atom.charge that is found in the nucleus of an atom.

Atoms have their Atoms have their electrons arranged electrons arranged in layers called in layers called shellsshells

1st level- 2 electrons max.1st level- 2 electrons max. 2nd Level- 8 electrons max.2nd Level- 8 electrons max. 3rd level- 18 electrons max.3rd level- 18 electrons max. 4th level- 32 electrons max.4th level- 32 electrons max.

Using the Periodic Table to Using the Periodic Table to understand makeup of atomsunderstand makeup of atoms Atomic NumberAtomic Number- Number - Number

of protons in the nucleus.of protons in the nucleus. Atomic MassAtomic Mass- Average of - Average of

the masses of the existing the masses of the existing isotopes of an element.isotopes of an element.

Mass numberMass number- the sum of - the sum of the protons and neutrons the protons and neutrons in its nucleus.in its nucleus.