Atoms And The Periodic Table Flashcards
Nucleus
Center of the atom. Made of protons and neutrons.
Proton
In the nucleus. Positive charge.
Neutron
In the nucleus. No charge.
Electron
Moving around outside the nucleus in a cloud. Negative charge.
Orbital
The regions in an atom where electrons are likely to be found.
Valence Electron
An electron in the outermost energy level of an atom.
Periodic Law
States that when elements are arranged by the number of protons, similarities in their properties will occur in a regular pattern.
Period
Horizontal rows in the periodic table.
Group
Columns in the periodic table.
Ion
Has a net electrical charge because the charges do not cancel completely as they did before.
Atomic Number
Tells how many protons are in an atom.
Mass Number
The number of protons plus the number of neutrons.
Isotope
Different version of an element. Different mass, but the same element because they have the same number of protons.
Atomic Mass Unit (amu)
Equal to exactly 1/12 of a carbon-12 atom.
Average Atomic Mass
A weighted average.
Metal
Most metals are shiny solids that can be stretched and shaped.
Nonmetal
All, but hydrogen, are found on the right side of the periodic table. May be solids, liquids, or gases. Solid nonmetals are typically dull and brittle and are poor conductors of heat and electricity.
Semiconductor
Can conduct under certain conditions.
Alkali Metal
Soft and shiny and reacts violently with water.
Alkaline-Earth Metal
Have two valence electrons.
Transition Metal
Found in groups 3-12 on the periodic table. Most are combined with other elements as an ore.
Halogen
Found in group 17. Form salts when they react with metals.
Noble Gas
Found in group 18. Exist as single atoms instead of molecules.
Mole
Large counting unit. A collection of a very large number of particles. About 6.022 x 10^23.
Avoagdro’s Constant
The number of particles, 6.022 x 10^23, in exactly one mole of a pure substance.
Molar Mass
The mass in grams of 1 mole of a substance.
Conversion Factor
A ratio that is derived from the equality of two units that can be used to convert from one unit to another.
