Answer is: D. Cl (chlorine).
The ionization energy (Ei) is the minimum amount of energy required to remove the valence electron, when element lose electrons, oxidation number of element grows (oxidation process).
Barium, potassium and arsenic are metals (easily lost valence electrons), chlorine is nonmetal (easily gain electrons).
Alkaline metals (in this example, potassium) have lowest ionizations energy and easy remove valence electrons (one electron), earth alkaline metals (in this example, barium) have higher ionization energy than alkaline metals, because they have two valence electrons.
Nonmetals (in this example chlorine) are far right in the main group and they have highest ionization energy, because they have many valence electrons.
Atomic number of an element is the number of protons present in that element. It is unique for each element. The atomic number of carbon is 6.
The mass of a magnesium block that measures 2.5cm x 3.5cm x 1.5cm, the correct answer would be option “B.”
Hence, 5.1 * 10^-11 alpha particles is being emitted each second by the sample.
<h3>What is half life?</h3>
The term half life is the time taken for only half of the original amount of radioactive nuclides to remain.
Thus, we have that the half life is 432.2 years or 1.36 * 10^10 s.
k = 0.693/ 1.36 * 10^10 s
k = 5.1 * 10^-11 alpha particles per second.
Learn more about alpha particles:brainly.com/question/2288334
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