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La materia se compone de pequeñas
partículas llamadas átomos. ¿Cuál de los
siguientes científicos estableció que los
electrones giran alrededor de un núcleo en
varios niveles de energía?

A Joseph John Thomson
B Ernest Rutherford
C John Dalton
D Niels Bohr

The correct answer is D) Niels Bohr​

Explanation:

Bohr proposed a new atomic model, whereby he explains that electrons rotate around the nucleus at well-defined levels, describing circular orbits. Each orbit was called the energy level (it is called the main quantum number n, going from numbers 1 to 7). To make his model, Bohr studied the Hydrogen atom (it has a proton in its nucleus and an electron rotating around it).

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6