A. True.
Very true. The quicker or slower the reactants are used up the faster or slower the rate of reaction, and the faster or slower the products are formed, the faster or slower the rate of reaction.
Answer: All of these statements are true
Explanation:
Melting point help us to determine if a mixture is pure or has impurities by the virtues of it melting range..
The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element.
Answer:
Elements form compounds to satisfy the octet rule. Noble gasses never form compounds because they already satisfy the octet rule.
Explanation:
The octet Rule is the theory that an element will attempt to gain a valence of 8 by binding with another element in it's vicinity. This can happen in a variety of ways, but the main thing to remember is that they will take the "shortest path" to 8(I.e an element will sometimes lose an electron or 2 if it has a valence 1 or 2 to loop back around to 8, while an element with a valence of 6 or 7 will attempt to gain 2 or 1 electrons).
Valence of elements can be counted by group in the image attached.
Group 1 has a valence of 1, Group 2 has a valence of 2, then we move to group 13 which has a valence of 3, group 14 has a valence of 4, group 15 has a valence of 5, group 16 has 6, group 17 has 7, and group 18 is the noble gasses which have 8.