Download Atoms Introduction Notes and Vocabulary

Introduction to Atoms- Vocabulary and Notes
ATOM - smallest piece of an element that is still that element
ELEMENT - matter that is made of only ONE type of atoms.
Ex.: Iron, Silver, Carbon, Gold, Oxygen, and others located on the Periodic
Table of Elements.
PROTON – positively charged particle found in the nucleus of an atom /
It has the same mass as a neutron
NEUTRON- neutrally charged (no charge) particle found in the nucleus of an atom /
It has the same mass as a proton
ELECTRON- negatively charged particle that orbits the nucleus of an atom / very, VERY
small mass / these are important in chemical reactions because they bond with
other atoms. The mass of an electron is around 1/2000th that of a proton or
electron.
VALANCE ELECTRON- an electron found in the outer energy shell/level of an atom
that can chemically bond with another atom or atoms
NUCLEUS- central portion of an atom which contains the protons and neutrons / the
nucleus contains almost all of the mass of the atom
ATOMIC NUMBER- found on the Periodic Table, this tells the number of protons
found in the nucleus and the number of electrons outside the nucleus
MASS NUMBER-found on the Periodic Table, this gives the average mass of an atom,
measured is AMUs / also gives the total of the number of neutrons and protons,
added together
AMU- “Atomic Mass Unit” – SI unit used to measure the tiny mass of atoms
ISOTOPE- atoms of the same element that have different numbers of neutrons because
they have gained or lost neutrons
(Example carbon-12, carbon-13, carbon-14)
ION- an atom that is no longer neutrally charged because if lost OR gained an electron
These atoms will have a "+" or a "-" beside them to represent it as an ion
(Example Na+ or Cl-)
CATION - a positively charged ion
ANION - a negatively charged ion
ELECTRON CLOUD- area of space outside the nucleus where electrons can be found in
their orbit
ENERGY SHELL/LEVEL- orbital spaces electrons fit in outside the nucleus, similar to
the planets orbiting the sun / Each level can only hold a certain number of electrons
Energy Level number
or "Quantum Number"
Energy
Level/
(and the math formula in case
Shell
you forget the capacities)
Letter
1
(1x1) x 2 =
K
2
(2x2) x 2 =
L
3
(3x3) x 2 =
M
4
(4x4) x 2 =
N
5
(5x5) x 2 =
O
6
(6x6) x 2 =
P
Electron Capacity of each
Energy level/shell
2
8
18
32
50
72
* Energy shells are filled starting with the lowest level first and moving toward the
outermost shell until all electrons of an particular element are placed.
* There are "sub-levels" besides the actual levels so each shell may not be "full"
# of PROTONS = the atomic number
# of Electrons = the atomic number
# of NEUTRONS = the rounded atomic mass minus the atomic number
(rounded atomic mass – atomic number = # of neutrons)
* Know the symbols for the 25 common elements. (knowing the atomic number of these
elements would be a good idea too)
* If the nucleus of an atom were the size of a penny, the electron cloud would extend out
a distance of 20 football fields!
* Most of an atom is open space.