true or false biology sections 1-3

false

a combination is a substance formed when two or more different elements combine.

true

a mixture is a combination of two or more substances which each substance retains its individual characteristics.

true

a mixture of sand is a heterogenous mixture.

false

a suspension is a homogenous mixture which water is mixed with a substance that does not dissolve in it.

false

a suspension is a mixture that has a uniform composition throughout.

true

atoms of the same element that have different numbers of neutrons are called isotopes

false

in a mixture, the solvent is the substance that is dissolved.

false

on the periodic table, each element has a unique name and formula.

false

the period of an element is the amount of time it takes for half of a radioactive isotope to decay.

false

the periodic table is organized into horizontal rows, called periods, and vertical columns, called elements.

false

the two main types of chemical bonds are covalent bonds and van der Waals forces.

true

water is composed of hydrogen and oxygen