Answer
36.45 u; X = Cl
Explanation:
The atomic mass of X is the <em>weighted averag</em>e of the atomic masses of its isotopes.
We multiply the atomic mass of each isotope by a number representing its relative importance (i.e., its percent of the total).
Set up a table for easy calculation
.
0.7577 × 34.969 u = 26.496 u
0.2423 × 36.965 u = <u> 8.9566 u
</u>
TOTAL = 36.45 u
X = Cl
<u>Answer:</u> The wavelength of an electron is 
<u>Explanation:</u>
To calculate the wavelength of a particle, we use the equation given by De-Broglie's wavelength, which is:

where,
= De-Broglie's wavelength = ?
h = Planck's constant = 
m = mass of electron = 
v = velocity of electron = 
Putting values in above equation, we get:


Hence, the wavelength of an electron is 
This would be the stratosphere. which is the second layer of the atmosphere.
Explanation:
I'll give you a real answer later need points for test questions sorry
Answer:
C
Explanation:
Na has an electron configuration of 2,8,1
it forms an ion by losing 1 electron thus gaining a 1+ charge