<span>Boron has a lot of different isotopes, most of which having a very short half life (ranging from 770 milliseconds for Boron-8 down to 150 yoctoseconds for boron-7). But the two isotopes Boron-10 and Boron-11 are stable with about 80.1% of the naturally occurring boron being boron-11 and the remaining 19.9% being boron-10. The weighted average weight of those 2 isotopes has the value of 10.81.
The reason they use the average mass of an element for it's atomic weight is because elements in nature are rarely single isotopes. The weighted average allows us to easily compare relative number of atoms of one element against relative numbers of atoms of another element assuming that the experimenters are getting isotope ratios close to their natural ratios.</span>
<u>Answer</u>:-
Name of element = Lead
Symbol ♾ of Lead = Pb
Atomic no. = 82
Atomic mass = 207.2 amu
No. of protons = 82
No. of electrons = 82
Yes, lead(Pb) is a metallic element and certainly it has 6 electron shells which means 6 energy level.
If you find anything unclear you can ask me...
Answer:
Explanation:
1. Calculate the work
w = - pΔV = -4.3 atm × (43 L - 20 L) = -4.3 × 23 L·atm = -98.9 L·atm
2. Convert litre-atmospheres to joules
The negative sign indicates that the work was done against the surroundings.
Scientists prevent the nonpolar perfluorocarbons
in Oxygent from separating from the water by adding surfactant.
<u>Explanation:</u>
The collection of oxygen from lungs and transporting it all those tissues present in the human body and taking carbon dioxide back to lungs are the main functions of the hemoglobin. But, instead of this hemoglobin, When perfluorocarbons
, a nonpolar chemical is used to perform the same function for the oxygen transportation, the nonpolar chemical may not mix well with the water when this perfluorocarbons is taken through a water-based saline
.
For this purpose an addition of a chemical called surfactant is done. This will enhance the chemical bonding between the non polar chemical and water. The perfluorocarbons spreads into some droplets and gets coated with this bonding substance. Thus it gets attached to the water.
