Exam 12: Atoms and the Periodic Table

An electron de-excites from the fourth quantum level to the third and then directly to the first. Two frequencies of light are emitted. How do their combined energies compare to the energy of the single frequency that would be emitted by de-excitation from the fourth level directly to the first level?The combined energies of the two frequencies emitted by the one electrons is

Which of the following diagrams best represents the size of the atomic nucleus relative to the size of the atom? A B C D

Which of the following elements are in the same group as silicon (Si)?

The isotope lithium-7 has a mass of 7.0160 atomic mass units, and the isotope lithium-6 has a mass of 6.0151 atomic mass units. Given the information that 92.58 percent of all lithium atoms found in nature are lithium-7 and 7.42 percent are lithium-6, calculate the atomic mass of lithium, Li (atomic number 3).

Strontium, Sr (number 38), is especially dangerous to humans because it tends to accumulate in calcium-dependent bone marrow tissues (calcium, Ca, number 20). This fact relates to the organization of the periodic table in that strontium and calcium are both

Since atoms are mostly empty space, why don't objects pass through one another?

How might the spectrum of an atom appear if its electrons were not restricted to particular energy levels?

How does the wave model of electrons orbiting the nucleus account for the fact that the electrons can have only discrete energy values?

If an element has 18 protons and 20 neutrons and 18 electrons, which expression correctly identifies the element?

Which of the following statements describes an isotope?

Which element has the atomic number 9?

Does a shell have to contain electrons in order to exist?

Which of the following elements is a gas at room temperature?

Which are older, the atoms in the body of an elderly person or those in the body of a baby?

The following statement describes which subatomic particle best? It does not have an electrical charge.

Which of the following is not the name of a chemical family?

If a neutral element has the following chemical symbol, how many electrons does it have? O

If an element has 9 protons and 10 neutrons and 9 electrons, which expression correctly identifies the element?

Which of the following statements is false?

What does the following element description actually mean? U