Give me your best explanation on graphene carbon metal will give brainliest

Graphene is a semimetal with small overlap between the valence and the conduction bands. It is an allotrope of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice (figure 1).It is the basic structural element of many other allotropes of carbon, such as graphite, diamond, charcoal, carbon nanotubes and fullerenes.

Graphene Carbon along metal:

Metal oxides such as TiO2 and ZnO are large-band-gap  semiconductors, and they are photocatalytically active under  UV irradiation. These oxides are capable of interacting with  graphene oxide via carboxylic acid functional groups. Thus, mixing of two suspensions of GO and TiO2 or ZnO  results in the binding of oxide particles to graphene oxide flakes. These particles remain suspended in suspension,  minimizing any aggregation effects.

Graphene Oxide-Metal Nanoparticle Composites

Reduced  graphene oxide serves as a support material to stabilize  metal nanoparticles. For example, the synthesis of silver and  gold nanoparticles stabilized by graphene oxide sheets has  been reported by several research groups.These  composites have also been assembled as ultrathin films using  a layer-by-layer self-assembly technique.30 The procedure to  make these composites consists of mixing of GO and a metal  salt solution (AgNO3, HAuCl4, or H2PtCl6) and adding a dilute  borohydride solution. The chemical reduction process  reduces both GO and metal ions. The RGO acts as a support  to stabilize metal nanoparticles.

The resulting G-carbon composite exhibited competitive catalytic activity  and superior methanol tolerance compared to a commercial Pt/C catalyst. Furthermore, it demonstrated significantly higher catalytic efficiency than a Pt/C catalyst.

to make a supersaturated solution, make a saturated solution of sugar by adding 360 grams of sugar to 100 ml of water at 80 degrees celsius. when the water cools back down to 25 degrees, that 360 grams of sugar will still be dissolved even though the water should only dissolve 210 grams of sugar.

- 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