Answer:
C.11
Explanation:
Boron-11 makes up around 80% of all natural Boron. And, typically, the quickest way to determine the most abundant isotope of an element is to just round the atomic mass to the nearest whole number.
1. 5 electrons.
- Therefore, the 3d subshells blanks will be like this:
- ↑ ↑ ↑ ↑ ↑
2. 6 electrons.
- The 3d subshells blanks will be:
- ↑↓ ↑ ↑ ↑ ↑
3. 7 electrons.
- The 3d subshells blanks will be:
- ↑↓ ↑↓ ↑ ↑ ↑
Hope you could understand.
If you have any query, feel free to ask.
M = 22.8 g
V = 14.7 mL
ρ - ?
ρ = m/V
ρ = 22.8/14.7 = 1.55 g/mL
Answer is: <span>concentration of fluoride in the water in parts-per-million is 1 ppm.
</span>Parts-per-million (10⁻⁶) is<span> present at one-millionth of a </span>gram per gram of sample solution, f<span>or example mg/kg.
</span>m(fluoride) = 500 g · 1000 mg/g = 500000 mg.
m(water) = d(water) · V(water).
m(water) = 1 kg/L · 500000 L.
m(water) = 500000 kg.
arts-per-million = 500000 mg ÷ 500000 kg = 1 mg/kg = 1 ppm.
