Answer:
- 53 protons
- 131g
- Iodine
- Halogens
Explanation:
atomic no. = no. of protons
= 53 proton
mass = no. of protons + no. of
neutrons
= 53 + 78
= 131
Answer:
The particles in a solid are tightly packed and locked in place. Although we cannot see it or feel it, the particles are moving or vibrating in place.
Answer:
Neutrons = 11
Explanation:
To get the number of neurons an element has you have to subtract the number of protons from the atomic mass of that element.
The number of protons is equal to the atomic number of that element.
Atomic number = Number of Protons
So the number of protons is 25
Neutrons = Atomic mass - Number of Protons
Neutrons = 36 - 25
Neutrons = 11
Answer:
(a) Alkali metals: Francium (Fr)
(b) Chalcogens: Polonium (Po)
(c) Noble gases: Radon (Rn)
(d) Alkaline earth metals: Radium (Ra)
Explanation:
In the periodic table, the atomic mass increases down the group. Therefore, the last element of a group is the heaviest element of the group.
(a) alkali metals: The chemical elements that are present in group 1 of the periodic table, except hydrogen.
<u>The heaviest member of this group is francium (Fr)</u>
(b) chalcogens: The chemical elements that are present in group 16 of the periodic table
<u>The heaviest member of this group is polonium (Po)</u>
(c) noble gases: The chemical elements that are present in group 18 of the periodic table
<u>The heaviest member of this group is radon (Rn)</u>
(d) alkaline earth metals: The chemical elements that are present in group 2 of the periodic table.
<u>The heaviest member of this group is radium (Ra)</u>
<span>BaCl2+Na2SO4---->BaSO4+2NaCl
There is 1.0g of BaCl2 and 1.0g of Na2SO4, which is the limiting reagent?
"First convert grams into moles"
1.0g BaCl2 * (1 mol BaCl2 / 208.2g BaCl2) = 4.8 x 10^-3 mol BaCl2
1.0g Na2SO4 * (1 mol Na2SO4 / 142.04g Na2SO4) = 7.0 x 10^-3 mol Na2SO4
(7.0 x 10^-3 mol Na2SO4 / 4.8 x 10^-3 mol BaCl2 ) = 1.5 mol Na2SO4 / mol BaCl2
"From this ratio compare it to the equation, BaCl2+Na2SO4---->BaSO4+2NaCl"
The equation shows that for every mol of BaCl2 requires 1 mol of Na2SO4. But we found that there is 1.5 mol of Na2SO4 per mol of BaCl2. Therefore, BaCl2 is the limiting reagent.</span>
