Answer:
H₂S; CO₂; SiH₄
Explanation:
London dispersion forces are larger in molecules that are large and have more atoms or electrons.
A. H₂O or H₂S
H₂S. S is below O in the Periodic Table, so it is the larger atom. Its electrons are more polarizable.
B. CO₂ or CO
CO₂. CO₂ has more atoms. It is also linear, so the molecules can get close to each other and maximize the attractive forces.
C. CH₄ or SiH₄
CH₄. Si is below C in the Periodic Table, so it is the larger atom. Its electrons are more polarizable.
That would be the first option Ca(OH)2 + H2SO4 → CaSO4 + 2H2O.
The Ca replaces the H2 in H2SO4, and the H2 replaces the Ca is Ca(OH)2.
Explanation:
To delineate the the nature of the bonds that would be formed between the two elements, let us first write the electronic configuration of the two species;
Be = 2, 2
F = 2, 7
Beryllium is a metal with two valence electrons whereas fluorine is a halogen with seven valence electrons.
When Be loses two electrons it becomes isoelectronic with He;
Be → Be²⁺ + 2e⁻
Also, when fluorine gains an electron, it becomes isoelectronic with Ne;
F + e⁻ → F⁻
This loss and gain of electrons between the two elements creates an electrostatic attraction them and they enter into an electrovalent bond.
Hence;
Be²⁺ + 2F⁻ → BeF₂
