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Chapter 26, 27
Revise Chemical bonding and Chemical reactions.
Question | Answer |
---|---|
What is a compound? | A combination of two or more elements bonded chemically. |
Why do atoms combine to form compounds? | To have a stable (full) outer shell. |
What are the two ways that atoms can combine to form compounds? | Ionic and Covalent bonding. |
What is an ionic bond? | Ionic bonding is where one element give away an electron and the other takes it so both have full outer shells. |
Why do compounds form ionic bonds? | Because both elements are unstable naturally and so come together to balance out. |
What groups in the periodic table form ionic bonds together? | Group 1 and group 7. |
How many electrons does sodium want to lose when it bonds with chlorine? | 1 |
How many electrons does magnesium want to lose when it bonds with oxygen? | 2 |
What is a covalent bonds? | A covalent bond is when two elements become joined to share electrons. |
Why do compounds form covalent bonds? | An element with 4 electrons in its outer shell will bond with another element with 4 electron in its outer shell to share 8 electrons and become stable. |
How many electrons does hydrogen want to share when it bonds covalently? Why? | 1 because it needs an extra one to gain a full outer shell of 2. |
How many electrons does carbon want to share when it bonds covalently? | 4 so it fills to 8 up the outer shell. |
What are the differences between ionic and covalent substances? | Ionic bonds give away an electron and covalent share electrons. |