An ion having a 4+ charge and a mass of 49.9 amu has 2...

An ion having a $4+$ charge and a mass of $49.9$ amu has 2 electrons with principal quantum number $n=1,8$ electrons with $n=2$, and 10 electrons with $n=3 .$ Supply as many of the properties for the ion as possible from the information given. (Hint: In forming ions for this species, the $4 s$ electrons are lost before the $3 d$ electrons.) a. the atomic number b. total number of $s$ electrons c. total number of $p$ electrons d. total number of $d$ electrons e. the number of neutrons in the nucleus f. the ground-state electron configuration of the neutral atom

An ion having a $4+$ charge and a mass of $49.9$ amu has 2 electrons with principal quantum number $n=1,8$ electrons with $n=2$, and 10 electrons with $n=3 .$ Supply as many of the properties for the ion as possible from the information given. (Hint:
In forming ions for this species, the $4 s$ electrons are lost before the $3 d$ electrons.)
a. the atomic number
b. total number of $s$ electrons
c. total number of $p$ electrons
d. total number of $d$ electrons
e. the number of neutrons in the nucleus
f. the ground-state electron configuration of the neutral atom

Key Concepts

Atomic Number and Its Determination

The atomic number (Z) defines the number of protons in an atom's nucleus, and in a neutral atom it equals the total number of electrons. In the ion, the count of electrons is reduced by the ion’s positive charge (Z – charge). By knowing the ion’s charge and its electron distribution, one can work backward to determine Z.

Electron Configuration and Quantum Numbers

Electron configurations describe how electrons occupy orbitals characterized by quantum numbers such as the principal quantum number (n), which indicates the relative energy level and size of the orbital. Knowledge of the distribution among n = 1, 2, 3, etc., and among subshells (s, p, d) is crucial for understanding the electron arrangement in an atom or ion.

Ionization and Electron Removal Order in Transition Metals

In transition metals, even though the 4s orbital is filled before the 3d orbitals in the neutral atom, the electrons in the 4s orbital are actually removed first when ionizing. This counterintuitive removal order is essential for correctly determining the electron configuration of the corresponding ion.

Calculating Neutron Number from Mass Number

The mass number of an atom (usually approximated by its mass in amu) is the sum of its protons and neutrons. By subtracting the atomic number from the mass number, one can determine the number of neutrons present, an important parameter when considering nuclear properties.

Noble Gas Core Notation

Noble gas core notation is a shorthand for electron configurations, where the configuration of the nearest noble gas (e.g., [Ar]) represents a closed-shell structure. This notation simplifies the expression of electron configurations, especially for elements with many electrons, by highlighting the valence electrons that are often most relevant to chemical behavior.