Answer:
30, 50
Explanation:
Hello,
In this since an element's atomic number is equal to the number of protons in its atom, we can infer that selenium's atomic number is 30. Moreover, due to the fact the the neutrons are equal to the atomic mass minus the atomic number or the number of protons, by knowing the number of neutrons we compute the atomic as follows:
Thus, answer is 30, 50.
Best regards.
Iodine electron configuration is:
1S^2 2S^2 2P^6 3S^2 3P^6 4S^2 3d^10 4P^6 5S^2 4d^10 5P^5
when Krypton is the noble gas in the row above iodine in the periodic table,
we can change 1S^2 2S^2 2P^6 3S^2 3P^6 4S^2 3d^10 4P^6 by the symbol
[Kr] of Krypton.
So we can write the electron configuration of Iodine:
[Kr] 5S^2 4d^10 5P^5
Decomposition reaction D. 2H20⇒ 2H2 + O2
<h3>Further explanation
</h3>
Every chemical reaction involves a compound consisting of reactants and products
Reactants are compounds that react and form new compounds called products
There are several forms of reactions that can occur, including single replacement, double replacement, synthesis, decomposition, etc.
A. 2C2H6 + 702 ⇒ 4CO2 + 6H20
Combustion : reaction of Hydrocarbon and Oxygen
B. AgNO3 + LiCl → AgCl + LINO3
Double replacement : there is an ion exchange between two ion compounds in the reactant to form two new ion compounds in the product
C. Ca + MgS → CaS + Mg
Single replacement :one element replaces the other elements of a compound to produce new elements and compounds
D. 2H20⇒ 2H2 + O2
Decomposition : One compound breaks down into 2 components
Reaction: 2K₍s₎ + 2H₂O₍l₎ → 2KOH₍aq₎ + H₂₍g₎.
K - potassium.
H₂O - water.
KOH - potassium-hydroxide.
H₂ - hydrogen.
s - solid phase.
l - liquid.
aq - disolves in water.
g - gas.
Reaction is exothermal (release of energy) and potassium burns a purple flame. H<span>ydrogen released during the reaction reacts with </span>oxygen<span> and ignites.</span><span>
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