Chapter 4: Atoms and Elements Flashcards
What is an atomic mass unit?
One twelfth of the mass of a carbon atom containing 6 protons and 6 neutrons
Who developed the Nuclear theory of the atom?
Ernest Rutherford
What is a chemical symbol?
A one or two letter abbreviation for an element that appears directly below its atomic number
What is periodic law?
A scientific law which states that when elements are arranged in order of increasing relative mass, certain sets of properties recur naturally
What are metals?
A broad classification of elements in the periodic table which occupy the left side of the periodic table and have similar properties. They are good conductors of heat, are malleable, ductile, are often shiny, and tend to loose electrons when they undergo chemical reactions
What are nonmetals?
A broad classification of elements in the periodic table that occupy the right side of the periodic table. They are generally poor conductors of heat and electricity, and tend to gain electrons in chemical reactions.
What are metalloids?
This group of elements in the periodic table shares properties of both metals and nonmetals. They are often referred to as semi-conductors
What are transition elements?
This group of elements occupies the space between group 2A and group 3A ( or numbers 3-12 on some periodic tables) on the periodic table. The properties of these elements are less predictable
What are noble gases?
Chemically inert gases located in group 8A ( or 18)
What are alkali metals?
Located in group 1A, these metals are very reactive
What are alkaline metals?
Located in group 2A, these metals are reactive but slightly less so than alkali metals
What are halogens?
A group of highly reactive gases located in group 7A on the periodic table
