The force that holds atoms together is called a _________ ____________. (2 words)
What is a CHEMICAL BOND.
100
This is an atom, or group of atoms that have a charge.
What is an ION?
100
These are the electrons that are furthest from the nucleus and mostly loosely held by the nucleus. They are in the highest energy level.
What ar VALENCE ELECTRONS?
100
In a covalent bond, valence electrons are ___________ between atoms.
What is SHARED.
100
An alloy is a mixture made of...
...2 or more elements (one is a metal) that has the properties of a metal.
200
A _________________ is a neutral particle made up of 2 or more atoms joined by covalent bonds.
What is a MOLECULE?
200
When can ionic compounds conduct electricity?
When they are DISSOLVED IN WATER.
200
Valence electrons determine many properties of atoms, including the ways in which an atom can _________ with other atoms.
What is BOND?
200
A covalent bond in which valence electrons are shared unequally is called a ______________.
What is a POLAR BOND.
200
When metals bond, they give up their valence electrons and become ________________ charged atoms.
What is POSITIVELY.
300
A ion made up of more than one atom is called a _____________ ion.
What is POLYATOMIC?
300
Ionic bonds form as a result of the attraction between...
What are POSITIVE AND NEGATIVE IONS?
300
In an electron dot diagram, each dot represent a....
...VALENCE ELECTRON
300
When 2 pairs of valence electrons are shared it is called a _______________ bond. When 3 pairs of valence electrons are shared it is called a ______________ bond.
What are DOUBLE and TRIPLE bonds.
300
Why do people make alloys? Give 2 reasons.
They are STRONGER and LESS LIKELY TO REACT WITH AIR OR WATER than pure metals.
400
Ionic compounds form orderly, three-dimensional arrangements called ____________.
What are CRYSTALS?
400
Ionic compounds have high melting and boiling points because...
...THE IONIC BONDS ARE HARD TO BREAK, SO THEY NEED MORE HEAT TO BREAK THAN OTHER CHEMICAL BONDS.
400
How many valence electrons do the atoms in group 15 have? Will they try to gain or lose electrons when they form ionic bonds?
15, gain
400
How can you tell how many covalent bonds an atom can make? I will draw an atom on the board as an example for you to use in your answer.
Look at the unpaired valence electrons. An atom will form as many covalent bonds as the number of valence electrons it needs to make 8 (or 2 in Hydrogen's case).
400
Which forms stronger metallic bonds, an atom that can give up 1 valence electron or an atom that can give up 3 valence electrons?
3. The more electrons a metal atom can add to the "sea" of electrons surrounding it, the stronger the metallic bonds will be.
500
If neither atom is attracting the electrons more strongly than the other in a covalent bond, that covalent bond can be described as a ________________ bond.
What is NONPOLAR?
500
How can you tell the ratio of the ions in an ionic compound from its formula? Use magnesium chloride (MgCl2) to help explain your answer.
Look at the number of cations compared to anions. The 2 tells you there are 2 Cl- ions for every 1 Mg2+ ion. If there are no subscripts shown, the subscript is 1.
500
Do the noble gases (group 18) easily form chemical bonds? Use their number of valence electrons to help explain your answer.
No, they already have 8 valence electrons so they don't need any more. They are very un-reactive.
500
Why do molecular compounds have low melting and boiling points compared to ionic compounds?
Covalent bonds are much weaker than ionic bonds, so less energy (heat) is needed to break them.
500
Name 3 properties of metals or metal alloys. Hint: What properties make metals/alloys useful to people?