Answer:
mass number = protons + neutrons.
Explanation:
Together, the number of protons and the number of neutrons determine an element's mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number.
Answer:
Neon
Explanation:
The most stable Atoms are from the elements on group 18 of the predictable.
<span>2.70x10^7 pm^3
We will assume that the sodium atom closely approximates a sphere. So the expression for the volume of a sphere is
V = 4/3 pi r^3
V = 4/3 pi (186 pm)^3
V = 4/3 pi 6434856 pm^3
V = 26954261.78 pm^3
Round to 3 significant figures, giving 2.70x10^7 pm^3</span>
Answer:
3 will be the correct coefficient of CaBr2
Explanation:
In balancing a chemical equation, numbers should be assigned to both reactants and products as a numerical coefficients until all atoms of elements in both sides of the equation count equal.
The balanced equation of the reaction will be:
3CaSO4 + 2AlBr3 ==> 3CaBr2 + Al2(SO4)3
Looking at the unbalanced equation in the question, in the product Al2(SO4)3 there are 3 SO4 group. This will warrant putting 3 behind CaSO4 in order to balance the atoms of SO4 group. That operation will automatically put the number of Ca atoms in CaSO4 to be 3 therefore making CaBr2 to have 3 coefficient as in the balanced equation. This is to balance the number of Ca atoms in both sides to be 3.
