Sodium, Atomic mass: 22.989769 g
You can see in a periodic table
The absolute value of the difference in electronegativity (ΔEN) of two bonded atoms provides a rough measure of the polarity to be expected in the bond and, thus, the bond type. When the difference is very small or zero, the bond is covalent and nonpolar. When it is large, the bond is polar covalent or ionic.
Answer:
315.
Explanation:
Hello.
In this case, since the given number has five significant figures as the zero is to the right of the first nonzero digit (3), if it is required to report it with three significant figures, it is necessary to "cut" it at the first five without any rounding since the subsequent zero is less than five.
Thus the number turns out:
315
Best regards.
Answer: (3) silicon
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Silicon (Si)
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: ethane 
, propanone 
and water 
