unit 2 topic 6

Question 1

how many elements are there?

Answer 1

112

Question 2

What holds elements together when they form compounds

Answer 2

chemical bonds are formed when elements lose, gain, or share electrons

Question 3

what is an ionic compound

Answer 3

when atoms transfer electrons to other atoms

Question 4

what are molecular compounds

Answer 4

if atoms share electrons

Question 5

What are the key things to know about ionic compounds

Answer 5

• metal+non metals
• electrons are transferred from one atom to another, forming charged particles called ions which then join to make a compound
• bonds between atoms are strong
• always SOLID at room temperature
• conduct electricity

Question 6

what are the key things to know about molecular compounds

Answer 6

non-metal+ non-metal

• electrons are shared between the atoms to make the compound
• solid, liquid, or gas at room temperature depending on the compound
• does not conduct electricity

Question 7

what are the ways that elements change to ions and become stable

Answer 7

atoms gain or lose electrons in the valence (highest level) to become more stable like the noble gases. (stable octet)
- metals lose electrons, and nonmetals gain electrons to get the stable octet. When this happens the atoms become charged particles named IONS.

Question 8

when an atom gains an electron it has an overall _____ charge

Answer 8

negative

Question 9

when an atom loses electrons it has an overall_______ charge

Answer 9

positive

Question 10

what does IUPAC stand for

Answer 10

Internation Union of Pure and Applied Chemistry

Question 11

how do you make an ionic compound

Answer 11

electrons are transferred from the metal to the nonmetal then make an ionic bond.
ex. Na+ + Cl- = NaCl

Question 12

what are the rules of IUPAC

Answer 12

name the metallic element 1st as it is written on the periodic table.

2. name the nonmetallic element second, changing its ending to “ide”
3. positive and negative charges must equal zero. Use subscripts to indicate the number of ion in the compound. Or use the crossover rule.

Question 13

what are the naming rules of molecular compounds

Answer 13

1. write the entire name of the first element,
2. change the ending of the second element to ide
3. use the prefix to indicate the number of each type of atom in the formula

Question 14

to change from written name to the formula what do you do?

Answer 14

write the symbols for the elements in the same order as they appear in the name
2. use subscripts to indicate the nimbers of each type of atom.