Which of the following describes a heterogeneous mixture?
a
carbon monoxide, a toxic gas with the chemical formula co

b
simple syrup, a substance that has two parts sugar to every one part of water throughout

c
beach sand, a substance that can contain rocks, shells, metals and other substances distributed unevenly throughout

d
sulfur, a substance with atomic number 16 and the symbol s on the periodic table.

they are both synthetic elements

explanation:

d

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.

the answer is c. nacl