Helium - 4 isotope has 2 protons and 2 neutrons.
Its atomic number is 2 (the number of protons). Atomic number is the number of protons in the atom of an element and it identifies the element. All the isotopes of an element have the same atomic number (same number of protons). So, all the isotopes of hellium have 2 protons.
The number 4 that identifies the helium - 4 isotope is the mass number, i.e. the number of protons plus the number of neutron. So, helium-4 isotope has 2 protons and 2 neutrons. While, other isotopes of helium have 2 protons but different number of neutrons.
The atomic number enable us to deduce the number of electrons in an atom because the atoms are neutral, which implies that the positive and negative charge are equal. Given that the magnitude of the charge of electons and protons are equal but the sign is opposed (protons are positve and electrons are negative) the number of electrons in the atom equals the number of protonts. That is why the atomic number is also the number of electrons of the atom.
6.75 moles of H₂
Explanation:
We have the following balanced chemical reaction:
Mg + 2 HCl → MgCl₂ + H₂
From the chemical reaction we deduce that if 1 mole of Mg is reating with 2 moles of HCl then 8.30 moles of Mg is reaction with 16.60 moles of HCl, quantity which is over our available 13.5 moles of HCl. The limiting reactant is HCl.
Knowing this we devise the following reasoning:
if 2 moles of HCl produces 1 mole of H₂
then 13.5 moles of HCl produces X moles of H₂
X = (13.5 × 1) / 2 = 6.75 moles of H₂
Learn more about:
balancing chemical equations
brainly.com/question/13898428
#learnwithBrainly
Answer:
is this rearrange words then it would be
she did not phone me at the weekend
I hope it helps
Alkaline metal-group 1
Alkaline earth metals-group 2
halogens=group 7
noble gases-group 8 or o
transition metals are the actinides and the lactanides below the periodic table
