These masses are isotopes. By definition, isotopes of an element have the same number of protons as the given element, but different numbers of neutrons.
Answer and
Explanation
I believe the correct answer would be the last option. When an electrons moves from an excited state to the ground state, it would release energy. An electron in the excited state would mean that it contains high kinetic energy so to move to a lower state some of these energy should be released.
Answer: A. Most radiation reaching Earth from space is blocked by the atmosphere. Therefore, some telescopes must be placed above the atmosphere.
Explanation: Astronomers have a huge problem detecting radiation from space because the Earth's atmosphere blocks most of it and stops it from reaching the surface.
Hope this helps :)
The letter in parentheses after a chemical formula indicates c) the physical state of the substance.
The letters can be:
→ (s) for solid.
→ (l) for liquid.
→ (g) for gazeous.
→ (aq) for an aqueous solution (like NaCl (aq) - NaCl is dissolved in water)
