<span>One mol of NaCl (6.02 x1023 formulas) has a mass of 58.44 g. Concept 2. The relation between molecular (formula) mass and molar mass. To obtain one mole of copper atoms (6.02 x 1023 atoms), weigh out 63.55 g copper.</span>
Answer:
Take E(alpha particle energy) = 5.5 MeV (5.5x106x1.6x10-19)
If the charge on the lead nucleus is +82e(atomic number of lead is 82) = +82x1.6x10-19 C and the charge on the alpha particle is +2e = 2x1.6x10-19 C
Using dc = (1/4πεo)qQ/Eα we have
dc = [9x10^9x(2x1.6x10-19x82x1.6x10-19)]/5.5x10-13 = 6.67x10^-13m. = 6.67 x 10^-13 x 10^15 = 6.67 x 10^2fm
Note: 1meter = 10^15fentometer
Explanation:
This is well inside the atom but some eight nuclear diameters from the centre of the lead nucleus.
The atomic number of an element is characteristic to that element. Atomic number is the number of protons of that element.
Mass number is the sum of protons and neutrons of the element.
since protons and neutrons have a mass of 1 unit each, they together make up the mass of the element.
atomic number - number of protons - 92
mass number - number of neutrons + protons = 234
number of neutrons = mass number - atomic number
neutrons = 234 - 92 = 142
answer is 142