Answer:
1s^2 2s^2 2p^6 3s^1
Explanation:
electron configuration of an element gives description of the distribution of electron in it's orbital of the atom, the superscript symbolize number of electron been hold by them.
The element here is sodium, which is a alkali metal
mass number =23
Number of proton= 11
electron must be seen in thelowest-energy subshell that is available in the the 3s orbital,
Hence, the electronic configuration is
1s^2 2s^2 2p^6 3s^1
Answer:
(4) 266 moles
Explanation:
We have Dinitrogen Pentoxide N2O5
6.41*10^25 molecules are given
No of Moles of N2O5 =
=
= 106.5 mol
Now using Unitary Method
2 Mole of Nitrogen pentoxide require 5 mole of Oxygen to form N2O5
1 mole of N =
In 106.5 mole of N = = 266.25 mole
So, 6.41*10^25 molecules of N2O5 will require 266.25 mole of Oxygen atoms.
<span>Now. a 1m (that is a 1molal) solution is prepared by disssolving the molar mass in grams of the solute in 1kg or 1000g of solvent
Therefore a 0.244m solution is prepared by dissolving 32.0420*0.244 = 7.818g CH3OH in 1000g water
But you want to use only 400g water:
mass required = 7.818*400/1000 = 3.127g
Answer: dissolve 3.13g CH3OH in 400g water.</span>
Answer:
47.74 g
Explanation:
Given data:
Formula units of SrF₂ = 2.31 ×0²³
Mass of SrF₂ = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ formula units
2.31 ×0²³formula units × 1 mol / 6.022 × 10²³ formula units
0.38 mol
Mass of SrF₂:
Mass = number of moles × molar mass
Mass = 0.38 mol × 125.62 g/mol
Mass = 47.74 g