Question

1. choose the best answer.

____ developed an equation to better understand energy levels in an atom.
de broglie
heisenberg
bohr
schrödinger

1. choose the best answer.

an element that gains or loses an electron is a(n) ____.
valence element
positron
ion
isotope

Explanation:

For question 16:
Schrödinger developed the Schrödinger equation, which is used to describe the wave - like behavior of particles (such as electrons in an atom) and helps in understanding energy levels. De Broglie proposed the wave - particle duality concept. Heisenberg is known for the uncertainty principle. Bohr proposed a model of the atom with quantized energy levels but not the equation in the context of the wave - mechanical description of energy levels.
For question 17:
An ion is an atom or molecule that has gained or lost one or more electrons. A valence element is not a standard term in this context. A positron is the antiparticle of an electron. An isotope is an atom of an element with the same number of protons but different numbers of neutrons.

Answer:

1. Schrödinger
2. ion