Answer:
1) Ca: [Ar]4s²
2) Pm: [Xe]6s²4f⁵
Explanation:
1) Ca:
Its atomic number is 20. So it has 20 protons and 20 electrons.
Since it is in the row (period) 4 the noble gas before it is Ar, and the electron configuration is that of Argon whose atomic number is 18.
So, you have two more electrons (20 - 18 = 2) to distribute.
Those two electrons go the the orbital 4s.
Finally, the electron configuration is [Ar] 4s².
2) Pm
The atomic number of Pm is 61, so it has 61 protons and 61 electrons.
Pm is in the row (period) 6. So, the noble gas before Pm is Xe.
The atomic number of Xe is 54.
Therefore, you have to distribute 61 - 54 = 7 electrons on the orbitals 6s and 4f.
The resultant distribution for Pm is: [Xe]6s² 4f⁵.
Answer:
A). 92.02g
Explanation:
Equation of the reaction;
N2 (g)+ 2O2(g)------> 2NO2(g)
Note that the balanced reaction equation is the first step in solving any problem on stoichiometry. Once the reaction equation is correct, the question can be easily solved.
Reaction of one mole of nitrogen gas with two moles of oxygen gas yields two moles of nitrogen dioxide.
Mass of two moles of nitrogen dioxide= 2[14 + 2(16)] = 2[14+32]= 2[46]= 92 gmol-1
Therefore; Mass of two moles of nitrogen dioxide is 92
Rick Maurer i think that’s how you spell his last name
Explanation:
Well i mean clothes so cells make tissues which help organs clothes can technically help you if you fall it has layers so it woulf be as a cell?
