| A | B |
|---|
| Isotopes | Atoms of the same element with different numbers of neutrons |
| Mass number | # protons + # of neutrons |
| nucleus | Contains the protons and neutrons; contains all the mass of the atom |
| proton | positive particle,located inside the nucleus |
| neutron | located inside the nucleus, no charge |
| electron | negatively charged particle, found in the orbitals around the nucleus, has no mass |
| John Dalton | Proposed first atomic theory. Thought atom was a hard sphere. |
| JJ Thomson | Discovered the electron. Thought the atom was a positive sphere with negative particles embedded in it like "plum pudding" |
| Ernest Rutherford | Discovered the atom was mostly empty space with electrons outside the nucleus. |
| Neils Bohr | Found the movement of electrons around the nucleus to be like planets orbiting around the sun. |
| Mendeleev | Grouped elements according to their atomic mass in the first periodic table. |
| Mosely | Father of the modern periodic table which is grouped according to atomic number. |
| Group | The vertical columns on the periodic table |
| Period | The horizontal rows on the periodic table |
| 2-8-18-32 | The number of electrons in the first 4 energy levels |
| MAN | mass number = atomic number + neutrons |
| APE | atomic # = protons = electrons |
| Density | mass/ volume |
| units for density | g/cm3 or g/ml |
| Transition Metals | The most abundant metals and the most precious metals. |
| Mercury | The only liquid metal at room temperature |
| Bromine | The only liquid non-metal at room temperature |
| Halogens | Elements in Group 7A (17). Include F, Cl, Br, I |
| Alkali Metals | Elements in Group 1A. Include Na, K, Rb, Cs |
| Alkali Metals | The most reactive metals |
| Ductile | The property of metals that allows them to be drawn into thin wires. |
| Malleable | The property of metals that allows them to be pounded into thin sheets |
| Nonmetals are located….. | To the right of the stairstep |
| Metals are located……. | To the left of the stairstep |
