Answer:
Q8) True
Q9) First ionization energy
Q10) Metal oxides
Explanation:
A common property of group one elements (alkali metals) is their combination with water to form basic solutions. E.g 2K(s)+2H2O(l)→2KOH(aq)+H2(g).
The distance of the outermost electron in the atom from the nucleus is inversely related to the first ionization energy. As the distance between the outermost electron and the nucleus in group 17 elements gets larger, the corresponding first ionization energies of elements in the group gets smaller.
Group 1 elements can combine with oxygen to give metal oxides. E.g 4K + O2 --> 2 K2O
Five. The measurement 50,600 mg has five significant digits.
I presume that you are using the comma as a decimal separator.
The <em>rules for significant figures</em> are
1. Nonzero digits are always significant.
2. Any zeros between two significant digits are significant.
3. Final or trailing zeros are significant only if they are to the right of a decimal point.
• According to Rule 1, the <em>5 and 6</em> are significant.
• According to Rule 2, the <em>0 between the 5 and 6</em> is significant
• According to Rule 3, the <em>final two zeros</em> are significant.
Thus, there are five significant digits in the measurement 50,600 mg.
Note: If the comma is a thousands separator, the number has only three significant digits.
Explanation:
For a compound to show hydrogen bonding it is necessary that the hydrogen atom of the compound should be attached to more electronegative atom like fluorine, oxygen or nitrogen.
For example, 
, 
and 
all these compounds contain an electronegative atom attached to hydrogen atom.
Therefore, these pure compounds will exhibit hydrogen bonding.
Thus, we can conclude that out of the given options , and are the pure compounds which will exhibit hydrogen bonding.
They are about 4.5 billion years old. Hope this helps.
