Atoms and Elements Review

Which of the following are pure substances?

• mud

• iron

• salad

• air

• salt

Which of the following is a mixture?

• salt

• • salt water

• • milk

• oxygen

• air

What makes a homogenous mixture different from a heterogeneous mixture?

• Homogeneous mixtures are always solids

• • Homogeneous mixtures look uniform throughout

• • Heterogeneous mixtures cannot be separated

• Heterogeneous mixtures are chemically combined

1. Which of these is a heterogeneous mixture?

• cereals in milk

• • mixed nuts

• • brass

• sugar water

• air

Which of the following are compounds?

• water

• iron

• steel

• air

• salt

1. Why do atoms form compounds?

• to become more stable

• to change their size

• • to make mixtures

• • to stay reactive

1. Which group of elements are nonmetals?

• halogens

• noble gases

• • alkalis

• • lanthanides

• post-transition metals

Which statements are TRUE

• Metalloids are brittle but metals are malleable

• Metals are good conductors of heat unlike non metals

• Metalloids are shiny while non metals aren't

• Metalloids aren’t shiny unlike metals which are shiny

• Metals have low melting points unlike non metals which have high melting points

Which of the following is NOT a property of metals?

• dull appearance

• high thermal conductivity

• high electrical conductivity

• low melting point

• ductile and malleable

In what state do most nonmetal exist in room temperature?

• gas

• liquid

• solid

• plasma