Methods used to separate heterogeneous mixtures include the following: check all that apply. * Decanting
Filtration
Sifting

Filtration, Sifting and Decanting

Explanation:

Heterogenous mixtures can be seperated by filtration and sifting (Also known as sieving). Sifting is the process of parting a mixture using a sieve. Sifting is used to separate solid mixtures that contain molecules of varying sizes. Filtration is the process of separating a liquid from an insoluble solid. A common example is using a funnel and a coffee filiter to seperate the liquide from the insoluable solid. Although there are many other methods for filtration. You can also separate mixtures by decantation. Decantation is the process of separating a liquid from a solid/liquid by removing the liquid layer at the top from the layer of solid/liquid below.

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms