Download ATOMS / ATOMIC STRUCTURE NOTES Atom

ATOMS / ATOMIC STRUCTURE NOTES
Atom-the smallest possible piece of an element
Proton-the positively charged particle found in the nucleus of an atom
Neutron-the neutral (no charge) particle found in the nucleus of an atom
Electron- the negatively charged particle found on the outside of the nucleus of an atom
Nucleus-the dense core or center of an atom, it contains 99.9% of the mass of the atom
Electron shells-areas around the nucleus where electrons can be found
Valence electrons-the outermost electrons, the most important electrons because only they are
involved in chemical bonding
Atomic number-the number of protons in the nucleus of an atom, it determines the identity of the
element
Atomic weight-the average number of protons plus neutrons in the nucleus of an atom
Atomic mass unit(AMU)-the average weight of one proton or neutron
Isotope-an atom of the same element but with a different number of neutrons
How many protons, neutrons and electrons?
Protons= same as atomic number
Neutrons=atomic weight(round-off to nearest whole number)-atomic number
Electrons=same as atomic number(an atom is neutral, if it has 5 positive protons it will
have 5 negative electrons)
HOW TO DRAW AN ATOM
1. Start with the nucleus draw a bumpy circle, P= N=
2. Find element on the periodic table,
the row number (period) is the number
of electron shells
3. Fill in the electrons and number them