Properties and electron arrangement. Going down each column elements have similar properties and as they move left to right have the same number of electrons in their outer shell
Multiplying the subscripts within the empirical formula by this number gives you the molecular formula H2O2.
2) chemical
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4) physical
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9)physical / chemical
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An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed between a cation, which is usually a metal, and an anion, which is usually a nonmetal. A covalent bond involves a pair of electrons being shared between atoms.
Step 
<u>find the mass of a single washer</u>
Divide the total mass by the number of washers
Step 
<u>Convert kg to mg</u>
we know that
so
therefore
<u>the answer is</u>
