The model<span> of the </span>atom<span> has dramatically </span>changed<span> over many many years.We learn </span>atoms<span> make up different substances and are the smallest particles of matter. which can have subatomic particles that are very small portions of matter.at first scientist only thought there were electrons which are negatively charged.</span>
Answer: 1. C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur
2. B) 
3. B) Fluorine
Explanation:
1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.
Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7
Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.
2. A molecular compound is usually composed of two or more nonmetal elements. Example:
Ionic compound is formed by the transfer of electrons from metals to non metals. Example:
,
and 
3. For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas 
I think it looks good but some grammars are wrong i suggest trying to put it on grammarly and just check it out its just my suggestion and not doing this for points so you can delete this if it doesnt help
Answer:
B
Explanation:
The gravity accelleration values are the same for both planets.