Help in chemistry question?

Question

3. The atomic number of an element whose atoms have 9 electrons and 10 neutrons is ? 4.One isotope of carbon has 6 protons and 6 neutrons. The number of protons and neutrons of a second isotope of carbon would be ? 10. A certain element is a gas and dose not conduct electricity or heat. Which of the followin is a possible number of valence electrons for the atoms of this element? is it A. 1, B.2,C.3,OR D.6 11.Based on its position in the periodic table, the most likely charge of an iodide ion is A.1+, B.1-,C.2+or D.7-

Answer 1

3. In atoms, electron count = proton count, so 9 electrons ~> 9 protons. The element with 9 protons is Fluorine.

4. Carbon-14 is an isotope of carbon with 6 protons and 8 neutrons.

10. Being a gas and not conducting electricity says it's a nonmetal. Elements with 1, 2, or 3 valence electrons are all metals. 6 valence electrons is the only nonmetal.

11. Iodine is in column 7A, which gives it 7 valence electrons. According to the Octet Rule, elements want 8 valence electrons, which means Iodine wants to gain one electron. Electrons have a negative charge, so iodine would want a 1- charge.

Answer 2

the atomic number is defined as the no. of protons in atom. but protons=electrons (in neutral atom) so if ur atom is neutral then 9 is atomic number (it doesnt depend on neutrons)
2 isotopes have same atomic numbs but diff mass no therefore isotope must have 6 protons and any no. of neutrons but generally one or two neutrons more or less from the most common isotope as the nucleus wont be stable otherwise
since it is a gas it must be 6 as 1,2,3 valence electrons are possesed by metals (exceptions hydrogen and helium)
but it doesnt conduct electricity and heat thus it must be 6 as it doesnt hve free electrons to conduct . can be oxygen ,sulphur
-1 charge is shown most by iodine as it is grp17 element and must take one electron to attain noble gas configuration