compounds

Question 1

what is a compound?

Answer 1

they are substances formed by TWO OR MORE elements.

-the atoms of each are in FIXED PROPORTIONS throughout the compound and they’re held together by CHEMICAL BONDS.

Question 2

what joins together to make compounds?

Answer 2

atoms join together to make compounds.

• when elements react, atoms combine with other atoms to form compounds.
• making bonds involve atoms giving away, taking or sharing electrons. Only the electrons are involved- nuclei isn’t affected.

Question 3

compounds formed by metals

Answer 3

• a compound formed from a metal and a non-metal consists of ions. the metal atoms lose electrons to form positive ions and the non-metal atoms gain electrons to form negative ions.
• the opposite charges of the ions mean that they’re strongly attracted to each other. called ionic bonding.
• examples can be sodium chloride, magnesium oxide and calcium oxide.

Question 4

compounds formed by non-metals

Answer 4

• a compound formed from non-metals consists of molecules. Each atom shares an electron with another atom- called covalent bonding.
• examples can be hydrogen chloride gas, carbon monoxide and water.
• properties of a compound are usually different from the properties of the original elements.
• e,g if iron and sulfur react, the compound formed which is iron sulfide, a dull grey solid lump, and doesn’t behave anything like either element.

Question 5

formulas which will come in handy

Answer 5

carbon dioxide- Co2
ammonia-  NH3
water- H20
sodium chloride- NaCL
carbon monoxide- CO
hydrochloric acid- HCI
calcium chloride- CaCL2
sodium carbonate- Na2CO3
sulfuric acid- H2SO4