Neils bohr believed that electrons orbited the nucleus in different energy levels, based on strong support from

the 3rd option for make sense,so that's out

Dalton was the pioneer behind the atomic model,but he certainly didn't believe in the nucleus or electrons,much lest electron shells.

Chadwick's discovery was the discovery of the neutron,not electron energy levels.

Niels Bohr's model was an attempt at explaining the hydrogen atom's spectrogram,followed by Erwin Schrödinger.Thus the first option is the answer

yes they ca   is ur ansswerrr

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