If an element contains 8 electrons how many electrons will be placed in the 2nd valence shell? 6 2 8 5 11

The correct option is 6

Explanation:

The first shell of an atom can contain a maximum of two electrons and must be completely filled (with the two electrons) before the next electron shell is considered for filling. The second electron shell can contain a maximum of eight electrons.

If an element has 8 electrons, 2 of this electrons will occupy/completely fill the first electron shell, while the second shell will only contain the remaining 6 electrons.

NOTE: A neutral atom of an element with 8 electrons is oxygen.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer