Answer:
A3+ and B-
Explanation:
Elements in group 13 have outermost electron configuration, ns2np1 hence they form trivalent positive ions.
Elements in group 17 have outermost electron configuration ns2np5 hence they form univalent negative ions.
This implies that, if element A is in Group 13 and element B is in Group 17, the ions formed are A3+ and B-.
Answer:

Explanation:
You must calculate the moles of P₄O₁₀, convert to moles of P₂O₅, then convert to molecules of P₂O₅.
1. Moles of P₄O₁₀

2. Moles of P₂O₅
P₄O₁₀ ⟶ 2P₂O₅
The molar ratio is 2 mol P₂O₅:1 mol P₄O₁₀
3. Molecules of P₂O₅

Answer:
The weights of all elements are always compared to the Carbon-12.
Explanation:
The weights of all elements are always compared to the Carbon-12 because the mass of carbon is 12 which is the exactly the sum of protons and neutrons.
Oxygen was also considered the standard for some time but later this stander was rejected because in natural O¹⁷ and O¹⁸ were also present and this create the two different atomic mass tables.
AMU:
Atomic mass unit is define as the 1/12 the mass of an atom of carbon-12.
C12 has six neutron and six protons in the nucleus.
This unit is used to express the masses of atoms. We know that masses of atoms are very small and we do not have any such type of balance that can measure very small quantity. So that is way we use this scale to measure small quantity. For example, according to this scale
relative atomic mass of hydrogen is 1.008 amu
relative atomic mass of oxygen is 15.999 amu
relative atomic mass of uranium is 238.0289 amu
relative atomic mass of chlorine is 35.453 amu
The answer is D
Explanation: A RED FLOWER WITH ONE PART COLORED YELLOW
Although a scientific theories will support and wildly excepted, what might cause of the change?
the answer would be A, New Evidence.