# moles = mass (g) / Mr (relative atomic mass)
# moles = 458 / ((23*2)+32+(16*4)
# moles= 458 / 142 = 3.2253521126760...
= 3.23 moles
Answer:A
Explanation:
A nuclear reaction is balanced by ensuring that the Masses and charges of te reactants and products are exactly balanced on the left and right hand side of the reaction equation. If there are 60 mass units on the LHS and manganese has only 56 mass units then four mass units are left. If there is no charge on a neutron and there is a charge of 27 on the cobalt, then two charges are left. Four mass units and a charge of +2 corresponds to a helium which is actually an alpha particle.
Answer:
- The standard form of a chemical element is the natural mixture of several isotopes of the same element, which is atoms with the same number of protons but different number of neutrons, while an isotope is a particular kind of atom with a definite number of neutrons.
Explanation:
A <em>chemical element</em> is a pure substance formed by atoms with the same atomic number (number of protons). This is because it is the number of protons what identifies an element.
For example: oxygen is a chemical element, so oxygen is formed by only atoms of oxygen, and the atomic number of those atoms is 8, because every oxygen atom has 8 protons.
Nevertheless, some atoms of oxygen, may have different number of neutrons. Isotopes are different kind of atoms of the same element, which only differ in the number of neutrons. So, some atoms of oxygen will have 8 neutrons, other 9 neutrons, and other 10 neutrons (those are the stable isotopes of oxygen).
That difference in neutrons, is generally accepted that, does not modifiy substantially the chemical properties of the element, but the mass number. So, the isotopes with more neutrons wil be heavier, and the isotopes with less neutrons will be lighter.
- Mass number = number of protons + number of neutrons.
In general a chemical element is formed by a mixutre of isotopes of the same element.
C or A I may be incorrect but those are what I think it is
<u>Answer:</u>
a) number of neutrons
<u>Explanation:</u>
A sodium ion is formed when an electron is removed from a sodium atom. This means that the atom's number of electrons changes, but the number of neutrons remains unchanged.
However, as the number of electrons changes, the electric charge and the electronic structure change, which means that a sodium atom and a sodium ion do not have the same number of electrons, nor do they have the same electric charge or electronic structure.
Therefore, option a) is the correct option.
