Answer 1)
True
Explanation : To achieve an octet state in valence energy level, an oxygen atom will gain two electrons because as per the definition of octet rule, "The atoms<span> of mainly main-group elements tends to get combined in such a way that each </span>atom gets eight electrons in its last valence<span> shell, giving it the nearest same </span>electron<span> configuration as a noble gas". </span>
<span>
</span>So, in the case of oxygen which has 8 electrons and it will accommodate 2 electrons in its first shell and rest 6 in its last valence shell. In order to achieve the octet state it's easier for the atom to gain 2 electrons rather than giving up rest 6 electrons. Hence, it is true that it gains 2 electrons to complete the octet state.
Answer 2)
True
Explanation : The electronic configuration of Krypton [Kr] is
The abbreviated form of any element can be written as the nearest noble elemental configuration, along with the remaining extra distributed electrons in other orbitals;
Hence, the electron configuration of Cesium [Cs} is
which can be also written as Cs = [Kr]
Sodium and potassium are most likely to have similar physical and also chemical properties. They are in the same family called Alkali metals. Both will have the same valence electrons and are both very reactive.
Based on the balanced chemical reaction presented above, every mole of magnesium (Mg) yields one mole of diatomic hydrogen (H2). When converted to masses, every 24.3 grams of magnesium yields 2 grams of hydrogen.
From the given, there are 20 grams of magnesium available for the reaction. With this amount, the expected yield of hydrogen is 1.646 grams. To calculate the percent yield, divide the actual yield to the hypothetical yield.
*The case is impossible because the actual yield is greater than the theoretical yield.
If we assume that there had been a typographical error and that the actual yield is 0.7 grams instead of 1.7 grams, the percent yield becomes 42.5%. Thus, the answer is letter E.
Based on octet rule, elements would fill up their
outermost shell with 8 electrons to be stable. In this case, Carbon has 4
valence on its outer shell, Hydrogen has only 1 valence, while Bromine has 7. Therefore
the total valence electrons are:
total valence = 4*4 + 1*6 + 7*2 = 16 + 6 + 14
<span>total valence = 36</span>
During cellular respiration<span>, glucose is broken down in the presence of oxygen to produce carbon dioxide and water,energy is </span><span>released.</span>