Which of the following values best classifies a bond between 2 atoms as being ionic?
a. an electronegativity difference of greater than 1.7 between the atoms
b. an electronegativity difference of greater than 2.7 between the atoms
c. an electronegativity difference of less than 1.7 between the atoms
d. an electronegativity difference of less than 2.7 between the atoms

Answer is: A.An electronegativity difference of greater than 1.7 between the atoms.

Electronegativity (χ) is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

Atoms with higher electronegativity attracts more electrons towards it, electrons are closer to that atom.

For example, in ionic salt sodium fluoride (NaF), fluorine has electronegativity approximately χ = 4 and sodium χ = 1 (Δχ = 4 - 1; Δχ = 3), fluorine attracts electron and it has negative charge and sodium has positive charge.

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles

8 m/s because for him to get the same amount of energy as ray is putting out, bobby, who weighs half as much as ray, needs to run twice as fast.