Question 1

Which property of hydrogen made it a dangerous choice for filling the Hindenburg airship?

Accepted Answer

Hydrogen is highly reactive and flammable, which can lead to explosions when ignited.

Question 2

Why is helium used in modern blimps instead of hydrogen?

Accepted Answer

Helium is an inert gas with a stable electron configuration, making it nonflammable and safe.

Question 3

Which statement best explains why hydrogen atoms are so reactive?

Accepted Answer

Hydrogen atoms have one electron and seek to achieve a stable configuration by gaining or losing an electron.

Question 4

According to the Bohr model, what happens when an electron in a hydrogen atom absorbs energy?

Accepted Answer

The electron moves to a higher-energy orbit, becoming less stable.

Question 5

Which of the following correctly arranges visible light, X-rays, and microwaves in order of increasing wavelength?

Accepted Answer

X-rays \u003c visible light \u003c microwaves

Question 6

What is the relationship between the wavelength ($$\lambda) $$and frequency ($$
u) of $$electromagnetic radiation?

Accepted Answer

They are inversely proportional: as wavelength increases, frequency decreases.

Question 7

Which type of electromagnetic radiation has the highest energy per photon?

Accepted Answer

Gamma rays

Question 8

A patient receives a medical X-ray. Which property of X-rays makes them useful for imaging bones but also potentially harmful?

Accepted Answer

X-rays are ionizing radiation with enough energy to pass through soft tissue but not bone, and can damage biological molecules.

Question 9

Which of the following best describes the quantum-mechanical model of the atom?

Accepted Answer

Electrons are found in probability maps called orbitals, which show where an electron is likely to be found.

Question 10

Which electron configuration represents a ground-state carbon atom?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^2$$

Question 11

According to Hund’s rule, how do electrons fill orbitals of equal energy?

Accepted Answer

Electrons fill orbitals singly with parallel spins before pairing.

Question 12

Which of the following elements has the greatest number of valence electrons?

Accepted Answer

Chlorine (Cl)

Question 13

What is the electron configuration of sodium (Na, atomic number 11) using noble gas core notation?

Accepted Answer

$$[Ne] 3s^1$

Question 14

Which trend is observed as you move from left to right across a period in the periodic table?

Accepted Answer

Atomic size decreases, ionization energy increases, metallic character decreases.

Question 15

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons are the electrons in the outermost principal shell and are involved in chemical bonding.

Question 16

Which element is most likely to form a $$+1$$ cation to achieve a noble gas configuration?

Accepted Answer

Sodium (Na)

Question 17

A potassium ion pump in a nerve cell moves $$K^+$$ ions into the cell. Why is this process important for nerve function?

Accepted Answer

It creates a chemical gradient necessary for the transmission of nerve signals.

Question 18

Which of the following best explains why noble gases are inert?

Accepted Answer

They have a full complement of valence electrons, making them stable and unreactive.

Question 19

Which orbital is higher in energy in a multi-electron atom: $$4s or$$ $$3d$$?

Accepted Answer

$$3d is $$higher in energy than $$4s.$$

Question 20

Which of the following is a correct statement about the emission spectrum of hydrogen?

Accepted Answer

It consists of specific wavelengths, each corresponding to an electron transition between two orbits.

Electrons in Atoms and the Periodic Table: Chapter 9 Study Notes

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