Answer:
2
Explanation:
The total number of atoms in silver sulfate Ag2SO4 is 2
Let's start to understand this question by a simple combustion reaction involving oxidation of Ethane in the presence of Oxygen. When Ethane is burned in the presence of Oxygen it produces Carbon Dioxide and Water respectively. Therefore, the equation is as,
C₂H₆ + O₂ → CO₂ + H₂O
Above reaction shows the reaction and the equation is unbalanced. Balancing chemical equation is important because according to law of conservation of mass, mass can neither be created nor destroyed. Hence, we should balance the number of elements on both side.
LHS RHS
Carbon Atoms 2 1
Hydrogen Atoms 6 2
Oxygen Atoms 2 3
It means this equation is not obeying the law. Now, how to balance? One way is as follow,
C₂H₆ + O₃ → C₂O₂ + H₆O
LHS RHS
Carbon Atoms 2 2
Hydrogen Atoms 6 6
Oxygen Atoms 3 3
We have balanced the equation by changing the subscripts. But, we have messed up the chemical composition of compounds and molecules like Oxygen is converted into Ozone.
Therefore, we will change the coefficients (moles) to balance the equation as,
C₂H₆ + 7/2 O₂ → 2 CO₂ + 3 H₂O
LHS RHS
Carbon Atoms 2 2
Hydrogen Atoms 6 6
Oxygen Atoms 7 7
Now, by changing the coefficients we have balanced the equation without disturbing the chemical composition of compounds and molecules.
An isoelectronic series is where all of the ions listed have the same number of electrons in their atoms. When an atom has net charge of zero or neutral, it has equal number of protons and electrons. Hence, it means that the atomic number = no. of protons = no. of electrons. If these atoms become ions, they gain a net charge of + or -. Positive ions are cations. This means that they readily GIVE UP electrons, whereas negative ions (anions) readily ACCEPT electrons. So, to know which of these are isoelectronic, let's establish first the number of electron in a neutral atom from the periodic table:
Na=11; K=19; Rb=37; Cs = 55; Ca=20; S=16; Mg=12; Li=3; Be=4; B=5; C=6, Ar = 18
A. Na⁺: 11-1 = 10 electrons
K⁺: 19 - 1 = 18 electrons
Rb⁺: 37-1 = 36 electrons
B. K⁺: 19 - 1 = 18 electrons
Ca²⁺: 20 - 2 = 18 electrons
Ar: 18 electrons
S²⁻: 16 +2 = 18 electrons
C. Na⁺: 11-1 = 10 electrons
Mg²⁺: 12 - 2 = 10 electrons
S²⁻: 16 +2 = 18 electrons
D. Li=3 electrons
Be=4 electrons
B=5 electrons
C=6 electrons
The answer is letter B.
