The electron configuration of an atom in the ground state is 2-4. The total number of
occupied principal energy levels in this atom is
A) 1
B) 2
C) 3
D) 4

The total number of occupied principal energy levels in this atom is 2.

The energy levels are the locations where electrons are found and are

usually close to the nucleus. The energy levels 1s and 2s are involved and

occupied in the atom with a electronic configuration of 2-4 in its ground

state.

The 1s energy level has a maximum of 2 electrons which can fill it while the

2s energy level has a maximum of 8 electrons which can fill it.

This is why the total number of occupied principal energy levels in this atom

will be 2.

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2

Explanation:

The principal energy levels for an atom with a ground state electronic configuration is 2;

       K    L

       2    4

Principal quantum number represents the main energy level in which the orbital is located or the average distance of the orbital in the nucleus.

The principal quantum number takes whole number values such; i.e;

             n  = 1, 2, 3, 4, 5

For the given on the principal energy levels are 2.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol