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Phy. S. Chap. 17&18
Term | Definition |
---|---|
Element | Any pure substance that is made of only one kind of atom. |
4 elements | Air, Fire, Earth, Water |
There are _______ amount of elements | 117 |
There are _______ amount of natural occurring elements | 92 |
The 11 gases | H, He, N, O, F, Ne, Cl, Ar, Kr, Xe, Rn |
Monotomic elements | have 1 atom in natural state |
Noble gases | He, Ne, Ar, Kr, Xe, Rn |
Diatomic elements | H2, N2, O2, F2, Cl2, Br2, I2 |
Dmitri Mendeleev | arranged the elements into what eventually became the periodic table today |
Johann Dobereiner | placed the elements in order of increasing mass. (he called them triads. |
Periodicity | repetition of certain properties at regular intervals when elements were placed in order of atomic mass |
Henry Moseley | discovered how to use x-rays. He lead the revision of the periodic table. |
Metals | belong to families with few valence electrons |
Non-metals | hold their electrons tightly, so their properties are very different from metals |
the horizontal rows of the periodic table are called | periods or series |
The period number tells | how many main energy levels the elements in that period have in their ground state |
ground state | lowest energy state for electrons |
The more energy levels | the larger it is |
Cations | positive and have more protons |
Anion | negative and has less protons |
Electron affinity | deals with the strength of attraction of electrons to unbonded atoms |
electroegativity | deals with an atoms ability to attract and hold electrons when bonded to other atoms |
Covalent bonds | nonmetal /nonmetal; sharing |
ionic bonds | metal/ nonmetal ; giving away and taking electrons |
metallic bonds | metal/metal ; everyone sharing |