Answer:- B- 
Explanations:- Sharing of electrons takes place between non metals and the bond formed by the sharing of electrons is known as covalent bond. In first choice we only have a zinc metal and so no sharing of electrons would be possible here.
In third choice we have NaCl. Na is a metal and Cl is a non metal. The property of metals is to transfer its valence electrons to the non metal and the bond formed is known as ionic bond. So, third choice is also not correct.
In choice B we have sulfate ion that has sulfur and oxygen atoms and both of these are non metals. So, sharing of electrons is present here between the S and O atoms and covalent bonds are formed.
So, choice B- is the right answer.
Answer:
mass = 0.907865 grams
Explanation:
From the periodic table:
molar mass of Li = 6.941 grams
molar mass of F = 18.998 grams
Therefore:
molar mass of LiF = 6.941 + 18.998 = 25.939 grams/mole
number of moles can be calculated as follows:
number of moles = mass / molar mass
We have:
number of moles = 0.035 moles
molar mass = 25.939 grams/mole
Substitute in the equation to get the mass as follows:
0.035 = mass / 25.939
mass = 0.035 * 25.939 = 0.907865 grams
Hope this helps :)
Answer:
Explanation:
Examples of proteins include enzymes, antibodies and some hormones which help to speed up chemical reactions, defend against diseases and regulate the activity of cells.
The instrument is a Geiger counter and is used to measure radioactive level around people's bodies.
