Chemical Equations and Charge

The law of conservation of mass states that....

• Matter can be made
• Matter can be destroyed
• Matter can neither be made or destroyed

Is this balanced?...
Al + O₂ --> 2Al₂O₃

• Yes!
• NO!

Balance this equation...
HgO --> 2Hg + O₂

• It is balanced 
• 2HgO --> Hg + O₂
• 2HgO --> 2Hg + O₂

At the end of chemical reactions, what is the total mass of the reactants compared to the total mass of the products?

• the product is doubled
• the product is half the mass of the reactants
• the mass is the same
• the mass changes depending on the reaction

How many valence electrons does magnesium have?

• 6

• 12

• 2

• 10

What are valence electrons?

• electrons in the outermost energy level

• electrons in the innermost energy level

• positively charged ions

• energy used for attraction in a shell

How many valence electrons does elements in group 16 have?

• 16

• 1

• 6

• 0

What is an ion?

• a positively charged atom

• a negatively charged atom

• a neutral charged atom

• both a and b

What is a cation?

• a negatively charged ion

• an ion with many charges

• a positively charged ion

What defines the octet rule?

• Contains element symbol and valence electrons

• atoms of main-group elements tend to combine in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.

• The electrons in the outermost energy level of an atom that influence how an element will react with other substances