Answer: Air
Explanation: Pure air is a mixture of several gases that are invisible and odorless. Consists of 78% nitrogen, 21% oxygen, and less than 1% of argon, carbon dioxide.
<span>The answer is "D" where the number of collisions per unit area is reduced by one-half. Drawing back on the piston means the volume is increased. The pressure is reduced. There are fewer collisions when the pressure is reduced.</span>
The statement which is true is
Fluorine is more reactive than nitrogen because fluorine needs only one electron to fill its outermost shell.
<u><em>Explanation</em></u>
Fluorine has electron configuration of 1S²2S²2P⁵ while nitrogen has 1S²2S²2P³ electron configuration.
The 2P sub shell for nitrogen is half filled therefore it is sable than fluorine.
since p orbital can hold a maximum of 6 electrons ,Fluorine requires 1 electron to completely fill it's 2P sub shell which make it more reactive than nitrogen.
Break down the table into smaller sections. Memories period by period or if you like by group (like halogens or noble gases).
Just say the elements in order everyday 1-10 then when you get those 11-20 and continued.
