Write electron configurations for the following ions, and determine which have noble-gas configurations
Tl+
As3-
I -
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To determine the electron configurations for the given ions, we need to know the atomic numbers of the elements. The atomic number for each element you mentioned is:
Tl (Thallium): 81
As (Arsenic): 33
I (Iodine): 53
To write the electron configuration, we need to follow these steps:
1. Determine the total number of electrons for the neutral atom of each element.
2. Remove/add electrons according to the charge of the ion.
3. Write the electron configuration for the resulting ion.
Now let's write the electron configurations for each ion:
Tl+:
The neutral atom of Thallium (Tl) has 81 electrons. When it loses one electron to become Tl+, the electron configuration changes to [Xe]6s^24f^145d^10.
As3-:
The neutral atom of Arsenic (As) has 33 electrons. When it gains three electrons to become As3-, the electron configuration changes to [Ar]3d^104s^24p^6.
I-:
The neutral atom of Iodine (I) has 53 electrons. When it gains one electron to become I-, the electron configuration changes to [Kr]5s^24d^105p^6.
Now let's determine which of these ions have noble-gas configurations. Noble-gas configurations occur when the electron configuration of an ion matches that of a noble gas.
For Tl+:
The electron configuration [Xe]6s^24f^145d^10 is the same as the noble gas xenon (Xe). Therefore, Tl+ has a noble-gas configuration.
For As3- and I-:
The electron configurations [Ar]3d^104s^24p^6 and [Kr]5s^24d^105p^6 are not the same as any noble gas. Therefore, As3- and I- ions do not have noble-gas configurations.
In summary:
- Tl+ has a noble-gas configuration (matches Xe).
- As3- and I- do not have noble-gas configurations.
To write the electron configuration for an ion, you need to start with the electron configuration of the neutral atom and then add or remove electrons based on the ion's charge.
1. Tl+: The neutral atom of thallium (Tl) has the electron configuration [Xe] 6s² 4f¹⁴ 5d¹⁰ 6p¹. To form the Tl+ ion, one electron is removed from the 6s² orbital. Therefore, the electron configuration for Tl+ is [Xe] 4f¹⁴ 5d¹⁰ 6p¹.
2. As3-: The neutral atom of arsenic (As) has the electron configuration [Ar] 4s² 3d¹⁰ 4p³. To form the As3- ion, three additional electrons are added. Therefore, the electron configuration for As3- is [Ar] 4s² 3d¹⁰ 4p⁶.
3. I-: The neutral atom of iodine (I) has the electron configuration [Kr] 5s² 4d¹⁰ 5p⁵. To form the I- ion, one additional electron is added. Therefore, the electron configuration for I- is [Kr] 5s² 4d¹⁰ 5p⁶.
Now, let's determine which of these ions have noble-gas configurations. Noble-gas configurations are electron configurations that are identical to the electron configuration of a noble gas. In other words, the last completely filled energy level is the same.
1. Tl+: The electron configuration for Tl+ is [Xe] 4f¹⁴ 5d¹⁰ 6p¹. The noble gas that matches this configuration is xenon (Xe), so Tl+ has a noble-gas configuration.
2. As3-: The electron configuration for As3- is [Ar] 4s² 3d¹⁰ 4p⁶. The noble gas that matches this configuration is argon (Ar), so As3- has a noble-gas configuration.
3. I-: The electron configuration for I- is [Kr] 5s² 4d¹⁰ 5p⁶. The noble gas that matches this configuration is krypton (Kr), so I- also has a noble-gas configuration.
Therefore, Tl+, As3-, and I- all have noble-gas configurations.