Answer is: a. Rubidium (Rb) is more reactive than strontium (Sr) because strontium atoms must lose more electrons.
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).
Alkaline metals (group 1), in this example rubidium, have lowest ionizations energy and easy remove valence electrons (one electron), they are most reactive metals.
Earth alkaline metals (group 2), in this example strontium, have higher ionization energy than alkaline metals, because they have two valence electrons, they are less reactive.
Rubidium electron configuration: ₃₇Rb 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s¹; one valence electron is 5s¹ orbital.
Strontium electron configuration: ₃₈Sr 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s²; two valence electrons is 5s² orbital.
Answer:
Option A. 1.8×10²⁴ molecules.
Explanation:
Data obtained from the question include:
Number of mole of methane = 3 moles
Number of molecules of methane =?
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ molecules.
Thus, 1 mole of methane equally contains 6.02×10²³ molecules.
With the above information in mind, we can obtain the number of molecules in 3 moles of methane as follow:
1 mole of methane contains 6.02×10²³ molecules.
Therefore, 3 moles of methane will contain = 3 × 6.02×10²³ = 1.8×10²⁴ molecules.
Thus, 3 moles of methane contains 1.8×10²⁴ molecules.
The law of conservation of mass<span> states that </span>mass<span> in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the </span>law of conservation of mass<span>, the </span>mass<span> of the products in a chemical reaction must equal the </span>mass<span> of the reactants.
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