Answer:
For example, atoms in Groups 1 and 2 have 1 and 2 valence electrons, respectively. Atoms in Groups 13 and 18 have 3 and 8 valence electrons, respectively. Valence electrons are responsible for the reactivity of an element. They determine how "willing" the elements are to bond with each other to form new compounds.
Explanation: it might be 18 my guess:)
Al2O3 is the formula 2 and 3 are subscripts
Answer:
Selenium
Explanation:
Oxygen is present in the group sixteen.
This group consist of oxygen, sulfur, selenium, tellurium and polonium.
All of these have same number of valance electrons thus they show similar properties.
From the given list of elements only selenium is belong to oxygen family thus it has properties similar to the oxygen.
Electronic configuration of oxygen:
O = [He] 2s² 2p⁴
Electronic configuration of selenium:
Se = [Ar] 3d¹⁰ 4s² 4p⁴
While aluminium, boron and phosphorus are belongs to other groups that's why their properties are not similar to the phosphorus.
phosphorus is present in group 15.
Boron and aluminium are present in group 13.
A compound has to be chemically bonded, however, air is not chemically bonded.
This can be proven by freezing air. By freezing air, it yields different liquids at different temperature. Liquid nitrogen has a different boiling point than liquid oxygen.
If air was a compound, they would all have a single boiling point and a single freezing point.
Hope this helps :)
The correct answer choice from the statement above about investigated factors from lab results is :
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Option D is the correct answer
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So therefore, The correct answer choice from the statement above about investigated factors from lab results is :
Students who spend less time studying after school get lower math grade
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