<span>On the periodic table, the majority of elements are classified as "Metals"
In short, Your Answer would be Option A
Hope this helps!</span>
The change of state that has been given in the question is called sublimation. It is actually the process in which a solid gets directly converted to gas without changing into liquid. I hope that this is the answer that you were looking for and the answer has actually come to your desired help.
Answer:
4Al203 + 9Fe -> 3Fe3O4 + 8Al
Amount of Al on reactant side: 8
Amount of Al on product side: 8
Amount of O on reactant side: 12
Amount of O on product side: 12
Amount of Fe on reactant side: 9
Amount of Fe on product side: 9
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.
Given information : Sample of 
We need to find the moles of Chlorine in the given sample.
We can say that we need to find moles from the given atoms.
Relation between mole and atom is given by : 
Where 
is Avogadro number.
On solving the above equation , atoms(unit) gets cancelled out and we get 0.0286 mol.
In the given sample the moles of Chlorine (Cl) is 0.0286 mol , so option A is correct.
