Helium is in group 18 of the periodic

Question

table. How is helium different from
the other elements in this group?
(1 point)
Helium atoms have a full outer
energy level, while atoms of
the other elements in the
group do not have a full outer
energy level.
Helium atoms have 2
electrons, while atoms of the
other elements in the group all
have 18 electrons.
Helium atoms have valence
electrons in the first energy
level, while atoms of the other
elements in the group have
valence electrons in the
second energy level.
Helium atoms have 2 valence
electrons, while atoms of the
other elements in the group all
have 8 valence electrons.

Answer 1

The correct statement is:

Helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons.

Helium is unique among the noble gases because it has only two electrons, filling its first energy level, whereas the other noble gases (like neon, argon, krypton, etc.) have eight electrons in their outermost energy level.

Answer 2

Which element has atoms with
valence electrons in a higher
energy level than those of
calcium (Ca)?
(1 point)
oxygen (O)
bromine (Br)
lithium (Li)
cesium (Cs)

Answer 3

To determine which element has atoms with valence electrons in a higher energy level than those of calcium (Ca), we must first note that calcium (Ca) is in Group 2 and has an atomic number of 20. Its electron configuration is \(1s^2 2s^2 2p^6 3s^2\), meaning its valence electrons are in the third energy level (n=3).

Now let's look at the other options:

• Oxygen (O): Atomic number 8, electron configuration \(1s^2 2s^2 2p^4\). Valence electrons are in the second energy level (n=2).
• Bromine (Br): Atomic number 35, electron configuration \(1s^2 2s^2 2p^6 3s^2 3p^5\). Valence electrons are in the fourth energy level (n=4).
• Lithium (Li): Atomic number 3, electron configuration \(1s^2 2s^1\). Valence electrons are in the second energy level (n=2).
• Cesium (Cs): Atomic number 55, electron configuration \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 4p^6 5s^1\). Valence electrons are in the sixth energy level (n=6).

Given this information, both bromine (Br) and cesium (Cs) have valence electrons in a higher energy level than calcium. However, since the question is likely seeking a single answer, cesium (Cs) is the one with valence electrons in the highest energy level.

Therefore, the answer is:

cesium (Cs).

Answer 4

Which statement best
describes the arrangement
of electrons in an atom of
fluorine (F)?
(1 point)
There are two
electrons in the first
energy level and five
electrons in the
second energy level.
There are seven
electrons in the first
energy level and two
electrons in the
second energy level.
There are five
electrons in the first
energy level and two
electrons in the
second energy level.
There are two
electrons in the first
energy level and
seven electrons in
the second energy
level.

Answer 5

To understand the arrangement of electrons in a fluorine (F) atom, we need to know its atomic number, which is 9. This means that a fluorine atom has a total of 9 electrons.

The distribution of these electrons is as follows:

• The first energy level (n=1) can hold a maximum of 2 electrons. For fluorine, this level has 2 electrons.
• The second energy level (n=2) can hold a maximum of 8 electrons. For fluorine, this level has the remaining 7 electrons (9 total - 2 in the first level = 7 in the second level).

Thus, the correct statement that best describes the arrangement of electrons in a fluorine atom is:

There are two electrons in the first energy level and seven electrons in the second energy level.