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If all bond angles in AX₃ are the same, then which of the following are correct conclusions about AX₃?
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If all bond angles in AX₃ are the same, then which of the following are correct conclusions about AX₃?
(A) and (B) are answered well in the comments by Todd Minehardt and Techie5879. So, I'll summarise their points and clarify (C) to justify the answer (D).
(A) $\ce{AX3}$ must be polar.
Consider the case of $\ce{BH3}$ to disprove statement (A), since it is a non polar molecule with a trigonal planar structure (equal bond angles).
(B) $\ce{AX3}$ must be planar.
Consider the case of $\ce{NH3}$ to disprove statement (B), since it is has a trigonal pyramidal shape and isn't planar, but has equal bond angles.
(C) $\ce{AX3}$ must have at least 5 valence electrons.
Here, the valence electrons of the central atom is referred and not the total number of valence electrons in the molecule because, $\ce{AX3}$ has 3 bonds, thus, 6 electrons are involved in bonding at the very least. If 4 valence electrons are considered, that could equate to only 2 bonds, hence contradicting the existence of $\ce{AX3}$.
With that mentioned, consider $\ce{BH3}$, it has 3 valence electrons, less than the 5 stated in the question. Hence (C) is disproved.
With (A), (B), and (C) disproved, (D) is the correct option by elimination.
(D) $\ce{X}$ must be connected to the central atom via single or double bonds.
(A) and (B) are answered well in the comments by Todd Minehardt and Techie5879. So, I'll summarise their points and clarify (C) to justify the answer (D).
(A) $\ce{AX3}$ must be polar.
Consider the case of $\ce{BH3}$ to disprove statement (A), since it is a non polar molecule with a trigonal planar structure (equal bond angles).
(B) $\ce{AX3}$ must be planar.
Consider the case of $\ce{NH3}$ to disprove statement (B), since it is has a trigonal pyramidal shape and isn't planar, but has equal bond angles.
(C) $\ce{AX3}$ must have at least 5 valence electrons.
Here, the valence electrons of the central atom is referred and not the total number of valence electrons in the molecule because, $\ce{AX3}$ has 3 bonds, thus, 6 electrons are involved in bonding at the very least. If 4 valence electrons are considered, that could equate to only 2 bonds, hence contradicting the existence of $\ce{AX3}$.With that mentioned, consider $\ce{BH3}$, it has 3 valence electrons, less than the 5 stated in the question. Hence (C) is disproved.
With (A), (B), and (C) disproved, (D) is the correct option by elimination.
(D) $\ce{X}$ must be connected to the central atom via single or double bonds.
(A) and (B) are answered well in the comments by Todd Minehardt and Techie5879. So, I'll summarise their points and clarify (C) to justify the answer (D).
(A) $\ce{AX3}$ must be polar.
Consider the case of $\ce{BH3}$ to disprove statement (A), since it is a non polar molecule with a trigonal planar structure (equal bond angles).
(B) $\ce{AX3}$ must be planar.
Consider the case of $\ce{NH3}$ to disprove statement (B), since it is has a trigonal pyramidal shape and isn't planar, but has equal bond angles.
(C) $\ce{AX3}$ must have at least 5 valence electrons.
Here, the valence electrons of the central atom is referred and not the total number of valence electrons in the molecule because, $\ce{AX3}$ has 3 bonds, thus, 6 electrons are involved in bonding at the very least. If 4 valence electrons are considered, that could equate to only 2 bonds, hence contradicting the existence of $\ce{AX3}$. With that mentioned, consider $\ce{BH3}$, it has 3 valence electrons, less than the 5 stated in the question. Hence (C) is disproved.
With (A), (B), and (C) disproved, (D) is the correct option by elimination.
(D) $\ce{X}$ must be connected to the central atom via single or double bonds.
(A) and (B) are answered well in the comments by Todd Minehardt and Techie5879. So, I'll summarise their points and clarify (C) to justify the answer (D).
(A) $\ce{AX3}$ must be polar.
Consider the case of $\ce{BH3}$ to disprove statement (A), since it is a non polar molecule with a trigonal planar structure (equal bond angles).
(B) $\ce{AX3}$ must be planar.
Consider the case of $\ce{NH3}$ to disprove statement (B), since it is has a trigonal pyramidal shape and isn't planar, but has equal bond angles.
(C) $\ce{AX3}$ must have at least 5 valence electrons.
Here, the valence electrons of the central atom is referred and not the total number of valence electrons in the molecule because, $\ce{AX3}$ has 3 bonds, thus, 6 electrons are involved in bonding at the very least. If 4 valence electrons are considered, that could equate to only 2 bonds, hence contradicting the existence of $\ce{AX3}$.With that mentioned, consider $\ce{BH3}$, it has 3 valence electrons, less than the 5 stated in the question. Hence (C) is disproved.
With (A), (B), and (C) disproved, (D) is the correct option by elimination.
(D) $\ce{X}$ must be connected to the central atom via single or double bonds.
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