Answer:

Explanation:
Hello there!
In this case, for the given reactants side, we infer this is a double replacement reaction because all the cations and anions are switched around as a result of the chemical change, we infer that the products side include aluminum with nitrate and magnesium with sulfate as shown below:

However, we need to balance since unequal number of atoms are present at both sides, thus, we do that as shown below:

Thus, we make 6 Al atoms, 3 S atoms, 3 Mg atoms and 30 O atoms on each side in agreement with the law of conservation of mass.
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Answer: (C) Statements (i) and (iii)
Explanation: According to byjus.com, group VII elements are known as Halogens.
Not only that, but bbc.co.uk says " Atoms of group 7 elements all have seven electrons in their outer shell. This means that the halogens all have similar chemical reactions ."
It may just be (b) though as these are chemical reactions.
Answer: amu
Explanation: it stands for atomic mass unit and it is the measurement that’s used to measure the mass of atoms