Answer:
d
Explanation:
Valence electrons are in the outermost shell. They form chemical bonds with other elements, not any other electrons. Hope this helps!
AN element is composed from atoms with the same number of protons,
A compound contain two or more different elements
Hey there!
The number of vacancies per unit volume => ( Nv = 2.3*10²⁵ m⁻³ )
Avogrado's number => ( NA = 6.022*10²³ atoms/mol )
Density of material ( p ) in g/m³ :
1 g/cm³ = 1000000 g/m³ so:
7.40 * ( 1000000 ) = 7.40*10⁶ g/m³
Atomic mass = 85.5 g/mol
* Calculate the number of atomic sites per unit volume :
N = NA * p / A
N = ( 6.022*10²³ ) * ( 7.40*10⁶ ) / 85.5
N = 4.45*10³⁰ / 85.5
N = 5.212*10²⁸ atoms/m³
Therefore:
Calculate the fraction of vacancies :
Fv = Nv / N
Fv = 2.3*10²⁵ / 5.212*10²⁸
FV = 4.441*10⁻⁴
Hope that helps!
A is correct. If an atom has more protons than electrons it is positively charged, if more electrons than protons it is negatively charged. An equal number of each will make it neutral