Unit 5: Periodic Trends

The quantum mechanical model of the structure of an atom reevaluates which of these scientific findings?

• the organization of the periodic table of the elements

• Lewis's mechanism of chemical bonding

• the principles of radioactive decay

• Bohr's planetary model of the atom

Answer explanation

The quantum mechanical model refines Bohr's planetary model by introducing wave-particle duality and probability distributions, providing a more accurate description of electron behavior in atoms.

Tags

NGSS.HS-PS4-3

Which of these represents the electron configuration for chlorine at ground state?

• 1s²2s²2p⁶3s²3p⁵

• 1s²2s²2p⁶3s²3p⁶

• 1s²2s²2p⁶3s²3p⁴

• 1s²2s²2p⁶3s²3p⁸

Answer explanation

The correct electron configuration for chlorine (atomic number 17) is 1s² 2s² 2p⁶ 3s² 3p⁵, indicating it has 5 electrons in the 3p subshell, which is consistent with its ground state.

Tags

NGSS.HS-PS1-1

Which diagram correctly represents the Lewis electron - dot structure for boron (B) at neutral state?

• A

• B

• C

• D

Answer explanation

The Lewis electron-dot structure for boron (B) shows three valence electrons. Diagram A correctly depicts this with three dots around the symbol for boron, representing its neutral state.

Which of these elements has both the highest electronegativity and the highest ionization energy?

• hydrogen (H)

• iodine (I)

• fluorine (F)

• phosphorus (P)

Answer explanation

Fluorine (F) has the highest electronegativity and ionization energy among the given elements. Its strong attraction for electrons and the energy required to remove an electron are both greater than those of hydrogen, iodine, and phosphorus.

Tags

NGSS.HS-PS1-1

Based on its position in he periodic table, which element has 7 electrons in its highest energy while at ground state?

• nitrogen (N)

• chlorine (Cl)

• rubidium (Rb)

• manganese (Mn)

Answer explanation

Chlorine (Cl) is in group 17 of the periodic table and has 7 electrons in its highest energy level (valence shell) when in the ground state, making it the correct answer.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of these represents the Lewis electron - dot structure for silicon at ground state?

• A

• B

• C

• D

Answer explanation

Silicon has 4 valence electrons, represented by 4 dots around the symbol 'Si' in choice A. This accurately depicts its ground state electron configuration, making A the correct Lewis electron-dot structure.

Tags

NGSS.HS-PS1-1

Which periodic property decreases from left to right across the periodic table?

• atomic mass

• atomic radius

• ionization energy

• electronegativity

Answer explanation

The atomic radius decreases from left to right across the periodic table due to increasing nuclear charge, which pulls electrons closer to the nucleus, resulting in a smaller atomic size.

How many electrons are represented in the Lewis electron-dot structure of an element with 14 electrons and 14 protons in the neutral state?

• 2

• 4

• 8

• 12

Answer explanation

The element with 14 electrons is silicon. In its Lewis structure, the valence electrons are represented. Silicon has 4 valence electrons, which are shown as dots around the element symbol, making the correct answer 4.

Tags

NGSS.HS-PS1-1

What are valence electrons?

• electrons on the first orbital always

• nucleus

• the outermost shell

• the number of electrons on the outermost orbital

Answer explanation

Valence electrons are the number of electrons on the outermost orbital of an atom. They play a crucial role in chemical bonding and reactions, making the correct choice "the number of electrons on the outermost orbital."

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What is Electronegativity?

• The amount of energy released when an electron is added to a neutral atom or molecule in the gaseous state (quantitative)

• An atom's tendency and likeability to attract and bond with electrons (non quantitative)

• The energy required to remove an electron from a neutral atom in its gaseous phase.

• Idk. I wasn't paying attention.

Answer explanation

Electronegativity refers to an atom's tendency and likeability to attract and bond with electrons. This concept is qualitative, distinguishing it from other definitions related to energy changes.

Tags

NGSS.HS-PS1-2