Writing Formulas

Elements & Compounds Introduction

Multiple Choice

Which is an element?

• NaCl

• H₂

Multiple Choice

Which is a compound?

• Li

• Li₂O

Multiple Choice

Which is an element?

• CO

• Co

Multiple Choice

Which is a compound?

• NO

• No

Steps for writing the formula unit for a ionic compound:

• Figure out the charge on each ion involved on periodic table

• Figure out how many of each ion are required to form a compound with an overall charge of zero.

• Write the cation (metal) first, with a subscript indicating how many you need.Write the anion (nonmetal) second, with a subscript indicating how many you need.

Multiple Choice

Which is the formula for aluminum oxide?

• AlO

• Al₂O₂

• Al₂O₃

• Al₃O₂

Multiple Choice

What is the formula for calcium oxide?

• CaO

• Ca₂O₂

• CaO₂

• Ca₂O

Multiple Choice

What is the formula for lithium bromide?

• Li₂Br

• Li₁Br₁

• LiBr

• LiBr₂

Multiple Choice

The proper formula for magnesium hydroxide:

• MgOH
• Mg₂OH
• Mg(OH)₂
• Mg₂OH₂

Multiple Choice

What is the formula for copper(I) sulfate?

• CuSO₃
• CuSO4
• Cu₂SO₃
• Cu₂SO4

Multiple Choice

What is the correct name for the following compound?

Ca(NO₂)₂

• Calcium nitroxide

• calcium nitrite

• calcium nitrate

• calcium nitro dioxided

Multiple Choice

What is the formula for tetraphosphorous decasulfide?

• PS₁₀

• P₁₀S₄

• P₄S₁₀

• P₆S₅

Multiple Choice

Write the formula: tin(II) phosphite

• Sn₃(PO₃)₂

• Sn3PO8

• Sn2PO4

• Sn₃(PO₄)2

Multiple Choice

Write the formula: carbon monoxide

• CO

• CO₂

• OC

• C₂O₄