Smallest part of an element that keeps it unique. Nucleus is at the center, with electrons circling at various energy levels. Made of 3 particles.
+, found in nucleus, 1 amu
=, found in nucleus, 1 amu
-, found in energy levels, amu 0
Why is an atom neutral overall?
Protons and electrons with opposite charges have equal numbers in an atom.
Substance that can't be broken into simpler substances
- Made of one type of atom.
- Periodic Table lists all known elements.
- 1st letter uppercase, 2nd lowercase
- e.g. Na
Protons in an atom, and electrons in an atom that haven't bonded
- Round to nearest whole # for most common mass.
- Mass # = p+ + n0
Atomic Mass Unit:
Average mass of atoms
(Cell on Periodic Table)
- 7--Atomic #
- N--Element's symbol
- Nitrogen--Element's name
- 14.01--Atomic Mass