The charges for four ions are sodium (na) +1, calcium (ca) +2, fluorine (f) –1, and sulfur (s) –2. which would be an ionic bond that could form from any of these ions?
a. naca2
b. na2s
c. caf
d. fs

B.

Explanation: An ionic bond is formed when an element completely transfers its valence electron to another element. Ionic bond is formed between a metal and an non-metal.

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 is having an oxidation state of +1 and sulfur has an oxidation state of -2. Thus they combine to form neutral .

is having an oxidation state of +2 and fluorine has an oxidation state of -1. Thus they combine to form neutral . and not .

Ithink the answer would be a

Iassume the answer is 75 feet. inwards to outwards rather than outwards to inwards. probably be 75.hachures are stokes drawn in direction of the steepest slope. a series of short parallel lines drawn on a map to indicate topographic relief. it is actually called hachures on contour lines. the small marks in the center of the feature are called hachures.observe the picture attached