Answer:
The order of elements by volume-fraction (which is approximately molecular mole-fraction) in the atmosphere is nitrogen (78.1%), oxygen (20.9%), argon (0.96%), followed by (in uncertain order) carbon and hydrogen because water vapor and carbon dioxide, which represent most of these two elements in the air, are variable.
I copied and pasted but I hope this information is helpful :)
For #1, I'd say it's "It will usually bond to multiple atoms which can provide a total of 4 additional electrons."
2. Ionic (I'm quite certain because anions/cations (-1 & +1) are Ionic from what I recall, if that's true it's Ionic.
3. "comparison of the associated families to which the elements belong" and
"the difference in electronegativities" are what I would choose, as I mentioned in a comment earlier.
If I'm wrong let me know, but I am at least 80% sure that these responses are correct from what I remember in Chemistry.
Answer:
density, mass of a unit volume of a material substance. The formula for density is d = M/V, where d is density, M is mass, and V is volume. Density is commonly expressed in units of grams per cubic centimetre. ... Density can also be expressed as kilograms per cubic metre (in metre-kilogram-second or SI units).
Explanation:
The average acceleration is -5.0 m·s⁻².
The formula for acceleration (<em>a</em>) is
= 25 m·s⁻¹; 
= 0; 
= 5.0 s
∴ 
= -5.0 m·s⁻²
The negative sign tells you that the object is <em>slowing down</em>, i.e., it is <em>decelerating</em>.
