Chapter 4 & 5 Flashcards
What are valence electrons?
The electrons that have the highest electrons.
The number of protons in a neutral atom equals the number of ___________.
Electrons
What is an electron dot diagram?
Includes the symbol for the element surrounded by dots that represent valence electrons.
What is a chemical bond?
Force of attraction that holds atoms together as a result of the rearrangement of electrons between them.
What is atomic number?
Number above chemical symbol on periodic table; the number of protons in each atom of the element.
The number of valence electrons ____________ from left to right across the periodic table.
Increases
Each period begins with an element with ___ valence electron, and except for period one, each period ends in an element that ends in ___ valence electrons.
1 , 8
What group are noble gases in?
Group 18.
How many valence electrons are in noble gases?
8, except helium, which has 2
How many electrons does an element need to be stable?
8, except helium. They are unlikely to gain or loose electrons.
The reactivity of metals _______ from left to right across the periodic table.
Decreases
Are alkali metals reactive?
Yes, very. Each element is the most reactive one in its period
When do nonmetals become stable?
When they gain or share enough electrons to have 8 valence electrons.
Nonmetals usually combine with _______ by gaining electrons
Metals.
Atoms of metalloids can either _____ or ____ electrons
Lose or share
When does hydrogen become stable?
When it gains one electron to get to 2
What is an ion?
An atom / group of atoms that has an electric charge.
When a neutral atom ______ a valence electron, it becomes a positive ion.
Loses
When a neutral atom _____ a valence electron, it becomes a negative ion.
Gains
What are polyatomic ions?
Ions that are made of more than 1 atom.
What is an ionic bond?
The attraction between two oppositely charged ions.
What are ionic compounds?
The results of ionic bonding. They are typically crystalline solids with high melting points. They are good conductors.
What is a chemical formula?
A group of symbols that represents the ratio of elements in a compound.
What are subscripts?
They tell the ratio of elements in a compound.
How do you say an ionic compound.
The name of the positive ion + the name of the negative ion.
What is a crystal?
An orderly, 3D arrangement.
What is a covalent bond?
The chemical bond formed when 2 atoms share electrons.
The attractions between the shared electrons and the protons I the nucleus of each atom hold the atoms together in a _______ bond.
Covalent.
What is a molecule?
A neutral group of atoms joined together by a covalent bond.
What is a double bond?
When atoms share 2 electrons.
What is a triple bond?
When atoms share 3 electrons.
What are molecular compounds?
A compound that is made up of molecules. They are formed by covalent bonds. They are bad conductors and they have low boiling and melting points.
What is a nonpolar bond?
A covalent bond where electrons are equally shared.
What is polar bond?
A covalent bond in which electrons are shared unequally.
