Answer:
Protons: 2.
Electrons: 2.
Neutrons: 2.
Explanation:
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In this case, since an atom's atomic number is equal to the number of electrons, considering the electron configurations, taking into account that helium-4 is neither positively nor negatively charged, we can infer that the number of electrons equal the number of protons, which in this case are 2, due to the fact that is atomic number is 2.
Moreover, as helium-4's atomic number is 4 as a whole number, we compute the number of neutrons by using the shown below equation:

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Answer:
A flame test is an analytical procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic emission spectrum. The color of flames in general also depends on temperature; see flame color.
Explanation:
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Energy levels inside an are the specific that electrons can have when occupying specific orbitals. Electrons can be excited to higher by absorbing from the surroundings. Light is emitted when an electron relaxes from a high state to a lower one.