Chemistry Flashcards
Oxidation numbers
The number that represents the number of electrons lost or gained by an atom of that element in the compound
Valence electrons
Electrons of an atom located on the outer most shell, can be transferred or shared
ion
Electrically charged atom/group of atoms formed by the loss or gain of one or more electrons
Cation: (positive) created when electron is lost
Anion: (negative) created when an electron is gained
Sub-atomic particles
Particles of matter smaller than an atom
EX: electrons, protons, neutrons
Lewis Dot Diagram
Diagrams that show the bonding between atoms of a molecule and the line pairs of electrons
Bohr’s Model
Model that consists of a small, positively charged nucleus surrounded by negatively charged electrons
(The one with circles)
Periods tell us…
Number of protons in the nucleus increases (FROM LEFT TO RIGHT)
Reactivity of each element decreases (FROM LEFT TO RIGHT)
The number of shells in each element
Groups tell us…
Number of valence electrons
Groups are vertical
Metal vs. Nonmetal
METALS:
Chemical features: lose their valence electrons easily, good reactor
Physical features: good electrical and heat conductors, malleable (bendable), solid at room temp.
NONMETALS:
Chemical features: gain or share valence electrons easily, form acids
Physical features: poor conductors, solids, liquids or gas at room temp.
Ionic bonding
The complete transfer of valence electrons between atoms
Octet rule
Rule that states that atoms of low atomic number (<20) tend to combine where they each have 8 electrons in their valence shell
Chemical formula symbol and subscripts
Subscript refers to the number next to the symbol of an element, shows how many atoms are present
EX: H₂O (2 hydrogens present)
Atomic number
Number of protons in an atom, number at the top of element on periodic table
Atomic mass
Mass of an atom of a chemical element, approximately equivalent to the number of protons and neutrons
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