Answers 25-26 KCS18 Chemistry ICElectrons and the Periodic Table

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Which set of numbers gives the correct possible values of l for n = 2?

0, 1

0, 1, 2

0, 1, 2, 3

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What did Ernest Rutherford’s gold foil experiment demonstrate about an atom?

Each atom is composed of electrons and positive material.

The mass of the atom is evenly spread throughout the atom.

Neutrons are located in the center of the atom.

Positive charge occupies a very small volume in the atom.

Iron, an element with the chemical symbol Fe, is an important element. It is used to make steel and is part of the substance that transports oxygen throughout the human body.Which statement about Fe is supported by the modern atomic theory but not John Dalton’s theory?

The element iron is composed of small particles called atoms.

The electrons of iron have probable locations in a region of space around the nucleus.

Iron atoms combine with other atoms in whole number ratios to form compounds.

Chemical reactions that involve iron do not create new atoms of iron.

Who was the first to propose the existence of atoms?

John Dalton

Democritus

Joseph Proust

Ernest Rutherford

Which best explains why ionization energy tends to decrease from the top to the bottom of a group?

The number of orbitals decreases.

The number of neutrons decreases.

Electrons get closer to the nucleus.

Electrons get farther from the nucleus.

In which orbitals would the valence electrons for selenium (Se) be placed?

s orbital and f orbital

s orbital only

s orbital and p orbital

d orbital only

A single atom of an element has 11 protons, 11 electrons, and 12 neutrons. Which element is it?

Hydrogen has three isotopes 1H, 2H, and 3H. What is the difference between these three isotopes?

The number of protons ranges from 1 to 3.

The number of electrons ranges from 1 to 3.

The number of neutrons ranges from 0 to 2.

The number of protons ranges from 0 to 2.

How did Niels Bohr describe electrons in his atomic model?

Their energies can have any values.

Their exact positions cannot be known.

They have high probability to be found in certain regions.

They orbit the central nucleus in discrete paths.

Which characteristic is given by the angular momentum quantum number?

orbital size

orbital mass

orbital shape

orbital orientation

Which element is classified as an alkali metal?

The elements of which group are nonreactive?

halogens

alkaline earth metals

noble gases

alkali metals

Which element has the largest atomic radius?

Which of the following symbols would be included in the noble gas notation for an element that had valence electrons in the 5s subshell?

Which describes Ernest Rutherford’s experiment?

Positive particles are fired at gold foil. Most bounce back, but some pass through.

Negative particles are fired at gold foil. Most bounce back, but some pass through.

Positive particles are fired at gold foil. Most pass through, but some bounce back.

Negative particles are fired at gold foil. Most pass through, but some bounce back.

The diagram below shows some subatomic particles.Which of these statements best identifies the particle that is labeled with an X?

It is either a nucleus or a proton.

It is either a proton or a neutron.

It is either a neutron or an electron.

It is either an electron or a nucleus.

Which scientist is known for developing the planetary model of the atom?

Niels Bohr

Albert Einstein

Johannes Rydberg

Robert Millikan

Which of Dalton's ideas about the atom did J.J. Thomson's experiment disprove?

It disproved that atoms are divisible.

It disproved that atoms are indivisible.

It disproved that atoms contain protons.

It disproved that atoms contain electrons.

Which element has 32 protons in its nucleus?

phosphorus

cobalt

germanium

sulfur

Which is a correct set of values of m for one of the subshells of n = 2?

–1, 0, 1

–1, –2, 0, 1, 2

–1, –2, –3, 0, 1, 2, 3

–1, –2, –3, –4, 0, 1, 2, 3, 4

What is the atomic number of zirconium?

How many valence electrons does aluminum (Al) have available for bonding?

Which statement best describes how electrons fill orbitals in the periodic table?

Electrons fill orbitals in order of their increasing energy from left to right.

Electrons fill orbitals in order of their increasing energy from right to left.

Elements fill orbitals in order of increasing energy from top to bottom in each group.

Elements fill orbitals in order of increasing energy from bottom to top in each group.

To show the electron configuration for an atom, when would it be better to use an orbital notation than to use a written configuration with numbers, letters, and superscripts?

when the aim is to use less space

when the aim is to show electron spins

when the aim is to show orbital shapes in subshells

when the aim is to show electron distributions in shells

Among the elements of the main group, the general trend in the first ionization energy moving across a period is not followed between group 2 and group 13. Which best explains these exceptions?

The ionization energy decreases because the full s orbital shields the electron entering the p orbital.

The ionization energy increases because the full s orbital shields the electron entering the p orbital.

The ionization energy decreases because the stability of the half-full p subshell is increased.

The ionization energy increases because the stability of the half-full p subshell is increased.

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