Explanation:
1. Democritus proposes the existence of atoms
2. Dalton's atomic theory
3. J. J. Thomson discovers the electron
4. Rutherford's gold foil experiment
5. Bohr model
6. Schrödinger's Wave Mechanics model of the atom
The first idea about matter containing atoms dates back to Greek philosophers. One of them was Democritus .
In 1808 Dalton put forward his atomic theory
In 1897 J.J Thomson discovered cathode rays using his gas discharge tube experiment.
In 1911, Ernest Rutherford proposed the nuclear model of the atom using experiments on the gold foil.
Neils Bohr in 1913 suggested his own atomic model
Erwin Schrodinger formulated the wave equation of electrons
Learn more;
Dalton atomic theory brainly.com/question/1979129
Rutherford gold foil experiment brainly.com/question/1859083
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Your answer would be 0.024951344877489 but rounding it would be 0.025 moles
Answer : The energy of the photon emitted is, -12.1 eV
Explanation :
First we have to calculate the 
orbit of hydrogen atom.
Formula used :
where,
= energy of 
orbit
n = number of orbit
Z = atomic number of hydrogen atom = 1
Energy of n = 1 in an hydrogen atom:
Energy of n = 2 in an hydrogen atom:
Energy change transition from n = 1 to n = 3 occurs.
Let energy change be E.
The negative sign indicates that energy of the photon emitted.
Thus, the energy of the photon emitted is, -12.1 eV
Answer: Option (4) is the correct answer.
Explanation:
When sulfuric acid reacts with calcium hydroxide then it results in the formation of calcium sulfate and water.
The chemical reaction for the same will be as follows.
Thus, we can conclude that 
salt is produced when sulfuric acid and calcium hydroxide react completely.
