<span>Selenium has 6 valence electrons, shares four of them with the four F atoms and has a pair of electrons left over, so has l0 electrons in its outer energy level. Choice A</span>
Answer: single replacement reaction, 
Explanation:
A single replacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution.
A general single displacement reaction can be represented as :

As strontium metal is added to aluminum chlorate , strontium being more reactive than aluminium, displaces aluminium atom its salt solution and lead to formation of strontium chlorate and aluminum metal.

Answer:
During the debate, a colleague on the negative side argued that bullies do not pick on students based on clothing. Uniforms won’t protect students from bullying because clothing isn’t the only thing that bullies look at. Bullies may look at skin color or even the culture of a particular student.
Explanation:
Answer:
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The independent variable is the one that is changed by the scientist. To insure a fair test, a good experiment has only ONE independent variable. As the scientist changes the independent variable, he or she records the data that they collect.
Answer:
the compound formed between nitrogen and magnesium is Magnesium Nitride