Chemistry

[Igcse100]

Calcium and other minerals are essential for healthy teeth and bones. Tablets can be taken
to provide these minerals.
(a) Boron is a non-metal with a macromolecular structure.
(i) What is the valency of boron?
...........................................................................
(ii) Predict two physical properties of boron.
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..................................................................................................................................
(iii) Name another element and a compound that have macromolecular structures.
element …………………..
compound ………………………
(iv) Sketch the structure of one of the above macromolecular substance


what does macromolecules mean

 

[larina]

a)i) as boron is a non metal, it loses electrons. see the group number boron is in, then 8 minus (group number) to get the valency number.

ii) as boron is a nin metal, predict the properties of non metals, e.g. the are insoluble in water. and they donot conduct electricity.

iii) macromolecules are large molecules.
e.g diamond and quartz
so the element present in the macro molecule is carbon(diamond is made up of many carbon atoms)
and compound is silicon dioxide(quartz is made up of silicon and oxygen)

iv) for sketching, u can either draw the structure of diamond(macromolecule) or quartz(a macromolecule)
---->for daimond:- each carbon atom is covalently bonded with 4 other carbon atoms
---->for quartz:- each silicon atom is bonded to 4 oxygen atoms,or each oxygen atom is bonded with 2 silicon atoms.
i havent draw the structures...i hav explained then so u can draw urself

hope this helps

 

[MasterOfPuppets]

A macromolecule is essentially a very large molecule, formed by combining many elements or smaller molecules. Such as monomers combined to form polymers, or carbon atoms joined together in a giant structure to form diamond.
You will find attached the structure of a diamond drawn (each carbon atom is covalently bonded to four others). Note the bonds are drawn with different lengths to give a 3D effect, as macromolecules are 3-dimensional. If you do not draw it as such, you may lose a mark. If you want any further help please let me know.