click below
click below
Normal Size Small Size show me how
Chapter 17-18
9th grade Physical Science
Question | Answer |
---|---|
Element | any pure substance that is made of only one kind of atom |
Today there are _____ elememts | 117 |
The heaviest elements are all _________ and have VERY SHORT half lives so they are difficult to analyze | radioactive |
There are ___ naturally occurring elements | 92 |
Mercury (Hg) and Bromine (Br) are ________ at room temperature | liquid |
Hydrogen (H), Helium (He), Nitrogen (N), Oxygen (O2), Fluorine (F), Neon (Ne), Chlorine (Cl), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn) are ______ at room temperature | gases |
Monotomic elements | Helium, Neon, Argon, Krypton, Xenon, and Radon |
Diatomic elements | Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, Iodine |
Who created the periodic table | Dmitri Mendeleev |
Who placed elements in order of increasing MASS | Johann Dobereiner |
The repetition of certain properties at regular intervals when elements were placed in order of atomic MASS | Periodicity |
Periodic law | The properties of the elements vary with their atomic numbers in a periodic way |
Metals | Luster, Malleable, Conduct electricity, Ductile |
Non-metals | Lack luster, Brittle, Don't conduct electricity , not ductile |
The horizontal rows of the periodic table are called | Periods |
A period number tells how many ________ the elements in that period have in their GROUND STATE | MAIN ENERGY LEVELS |
The MORE energy levels an atom has, the _______ it is | LARGER |
THE SECOND LAW OF THERMODYNAMICS | the tendency for atoms to form bonds |
Octet rule | atoms generally are most stable when they have 8 electrons in their valence energy level |
When atoms gain and lose electrons they make | IONS |
Cations are _______ | positive |
Anions are _______ | negative |
Electron affinity | deals with the strength of attraction of electrons to UNBONDED ATOMS |
Atoms with _____ electron affinities will take or share electrons from other atoms | high |
Atoms with ____ electron affinities will lose their valence electrons | low |
Electronegativity | deals with an atom's ability to attract and hold electrons when BONDED TO OTHER ATOMS |
Covalent bonds | Non-metal/Non-metal; share electrons |
Ionic bonds | metal/non-metal; giving away and taking electrons |
Metallic bonds | metal/metal; everyone shares the electrons Electron Sea Theory |
Electron Sea Theory | Atoms with weak electronegatives usually have only a few loosely held valence electrons. These atoms bond by sharing their easily lost electrons among many atoms. |