Answer:
smallest is O then Se then K then Cs.
Explanation:
These trends exist. elements tend to get smaller as it completes it's shell since there is more attraction when it is complete. plus the further down the periodic table you go the bigger it is. there are more electrons which repulse each other and make it bigger.
Answer:
6
Explanation:
bromine has 1, hydrogen has 4 and nitrogen has 1 therefore equaling 6
<span> endothermic is the answer
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2Mg+O₂⇒2MgO
It can be a combustion reaction, or it can be a combination reaction
3.5 x 10^-4 is the answer ! :)