I think its A because some scientist from the Department of Physics of Northeastern University found out that is not a part of Dalton's atomic theory.
elements have equal number of protons and neutrons
the condensed format is when the closest noble gas with the closest electron configuration is given, this closest noble gas atomic number should be lesser than the atoms atomic number
atomic number of Kr is 36
1 electron in 5s subshell and 7 electrons in 4d subshell.
there's a total of 36 + 1 + 7 = 44 electrons
atomic number of the atom is 44
element with atomic number 44 is Ruthenium - Ru
answer is Ru
Answer:
it has an equal number of neutrons and electrons
Explanation:
Number of protons always equal number of electron, but that's the case with a neutral atom. A neutral atom is an atom of any element that has no electric charge over it. This implies that it has same number of protons and electrons in it.
Answer:
The retention factor of an ion is 0.10 .
Explanation:
Retention factor is defined as ratio of distance of distance traveled by solute to the distance traveled by solvent on chromatogram.

We have:


The retention factor of an ion :

Answer is: Ksp for strontium arsenate is 2.69·10⁻¹⁸.
Balanced chemical reaction (dissociation):
Sr₃(AsO₄)₂(s) → 3Sr²⁺(aq) + AsO₄³⁻(aq).
s(Sr₃(AsO₄)₂) = 0.0650 g/L.
s(Sr₃(AsO₄)₂) = 0.0650 g/L ÷ 540.7 g/mol = 1.2·10⁻⁴ mol/L.
s(Sr²⁺) = 3s(Sr₃(AsO₄)₂).
s(AsO₄³⁻) = 2s(Sr₃(AsO₄)₂).
Ksp = s(Sr²⁺)³ · s(AsO₄³⁻)².
Ksp = (3s)³ · (2s)².
Ksp = 108s⁵.
Ksp = 108 · (1.2·10⁻⁴ mol/L)⁵ = 2.69·10⁻¹⁸.