USA Test Prep

Another term for having a fixed, discrete amount of energy is quantized energy.

Although the Bohr model and the quantum mechanical model differ in how electrons are located in an atom, they both agree that each electron's energy is fixed. Another term for this is ________.

The electrons are filled in the orbitals in increasing order of energy. The 21st electron will enter the 3d orbital as it has lower energy than the 4p orbital. The energies of the orbitals increase in the order 1s,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s.

Calcium (atomic number 20) has electron configuration 1s2,2s2,2p6,3s2,3p6,4s2. The atomic number of scandium is 21. Which orbital does the 21st electron enter?

Currently, scientists know the energies of electrons but only approximate areas (orbitals) where the electrons are probably located. This is a central idea in the quantum mechanical model. The Heisenberg uncertainty principle states that an electron's position & momentum (energy) cannot both be known with certainty simultaneously.

Determine which statement is true.

Those energy levels that are closest to the nucleus contain the smallest amount of energy. Electrons in the 3rd energy level would have the smallest amount of energy of the levels listed.

Electrons with the smallest amount of energy would occupy the principal quantum energy level of

An important aspect of the Bohr model is that the electrons were stated as having a fixed, discrete amount of energy. This is what distinguished the electrons in different "orbits" (energy levels).

How did Bohr answer the objection that an electron traveling in a circular orbit would radiate energy and fall into the nucleus?

Cesium is an alkaline earth metal. Its outer electronic configuration is ns1. Further, it is an element of the sixth period. So the outermost electron goes to 6s. The electronic configuration of cesium is 1s22s22p63s23p63d104s24p64d105s25p66s1.

Identify the electronic configuration of cesium.

The Bohr model taught that electrons move in fixed, circular paths whereas the quantum mechanical model shows the probability of finding an electron as a cloud in a certain energy level.

In the Bohr model of the atom, the electrons move in fixed, ________ paths around a dense, positively-charged nucleus. On the other hand, the quantum mechanical model shows the probability of finding an electron as a ___________ of negative charge.

In the Quantum Mechanical model, each electron's energy can be determined precisely but the location cannot. This energy is described using wave functions which are also known as orbitals.

In the quantum mechanical model, each allowed ______________ has a precisely known energy, but the location of the electron cannot be determined exactly; rather, the probability of it being at a particular point in space is given by the probability density.

The electrons in the outer shells determine how the atom behaves in chemical reactions. Atoms with complete valence shells, such as the noble gases, are the most chemically non-reactive, while those with only one electron in their outer shells, such as the alkali metals, are very reactive.

Neils Bohr published his model of the atomic structure in 1913. He introduced the theory of electrons traveling in orbits around the atom's nucleus, with electrons orbiting only in certain orbits called shells. Each shell can contain a fixed number of electrons. According to this model of the atom, the chemical properties of an element are mainly determined by

Unlike the planetary model, our model view is that the electrons move around the nucleus in an electron cloud.

The Bohr model of the atom suggest that the protons and neutrons are found in the nucleus and the electrons orbit the nucleus much like planets around the sun. How is our modern model of the atom different from this model?

According to the Aufbau principle, the electronic configuration of the given element should be 1s2,2s2,2p6,3s2,3p6,4s2,3d9. However, since fully filled orbitals have extra stability, the electronic configuration of the given element is b>1s2,2s2,2p6,3s2,3p6,4s1,3d10.

The atomic number of an element is 29. What is the electron configuration of this element?

The element with electronic configuration The electronic configuration of an element is 1s22s22p63s23p64s1 has a partially filled s-orbital. This is typical of a representative element. In a representative element the highest s-orbital or p-orbital is partially filled.

The electron configuration of an element is 1s22s22p63s23p64s1. Why is this a REPRESENTATIVE element?

This electron cloud model of aluminum has 3 energy levels with 3 electrons on its outer energy level. You can count each ring as an energy level. The outer energy level is the furthest from the nucleus.

This electron cloud model of aluminum has _______ energy levels with _______ electrons on its outer energy level.

Rubidium is an alkaline earth metal and the first element of fifth period. The outermost electron is added to the 5s-orbital. So the electronic configuration of Rb, atomic number 37, is 1s22s22p63s23p64s23d104p65s1

Which of these represents the correct electron configuration of rubidium? [Atomic number of rubidium is 37.]

According to VSEPR, orbitals fill up from lowest energy requirements to the highest energy requirements. Even though the principal quantum number 4 indicates a higher energy level than 3, the energy requirement to occupy 4s is lower than the energy requirement to occupy 3d. Therefore, the orbital that contains electrons with the greatest amount of energy would be 3d.

Which orbital would contain electrons with the greatest amount of energy?

Electrons are in "orbitals", regions of space where there is high probability of being found. The Bohr model focused on the idea that electrons were found in quantized circular orbits and traveled around the nucleus like the planets do around the sun.

Which statement refers to the quantum mechanical model?

Electrons in the s sublevel make a spherical path.

Within each energy level there are different sublevels that are created. Those electrons that have the lowest amount of energy follow paths that are spherical in shape. Which sublevel is associated with this shape?