Metallurgy and Ore Processing

Quantum Numbers, Atomic Orbitals, and Electron Configurations

• Each electron in an atom is described by four quantum numbers
• The first three quantum numbers (n, l, ml) specify the particular orbital of interest
• The fourth quantum number (ms) specifies how many electrons can occupy that orbital

Principal Quantum Number (n)

• n = 1, 2, ..., 8
• Describes the average distance of an electron from the nucleus, similar to the innermost electron shell
• Higher values of n indicate orbitals further from the nucleus and higher energy levels
• All orbitals with the same n value are in the same shell (level)

Angular or Orbital Quantum Number (l)

• l = 0, 1, ..., n-1
• Specifies the shape of an orbital with a particular principal quantum number
• Divides shells into smaller groups of orbitals called subshells (sublevels)
• Letter codes (s, p, d, f, g, h...) are used for identifying l
• Subshells with n=2 and l=1 are 2p
• Subshells with n=3 and l=0 are 3s

Magnetic Quantum Number (ml)

• ml = -l, ..., 0, ..., +l
• Specifies the orientation in space of an orbital of a given energy (n) and shape (l)
• Divides each subshell into individual orbitals
• Number of orbitals in a subshell = 2l+1 (e.g., s subshell has 1 orbital, p subshell has 3 orbitals)

Spin Quantum Number (ms)

• ms = +1/2 or -1/2
• Specifies the orientation of the spin axis of an electron
• An electron can spin in only one of two directions (sometimes called "up" and "down")
• The Pauli exclusion principle states that no two electrons in the same atom can have identical values for all four quantum numbers

The Aufbau Process

• The hypothetical process of building up complex atoms by progressively adding protons and electrons to the simplest atom (hydrogen)
• The order of filling atomic orbitals in progressing from a simpler to a complex atom is considered in this process

Periodicity

• Trends or recurring variations in element properties with increasing atomic number
• Caused by regular and predictable variations in element atomic structure
• Arranged elements in order of increasing atomic weight to organize them according to periodic properties
• Elements within a group (column) exhibit similar characteristics
• The rows of the periodic table (periods) reflect the filling of electron shells

Occurrence and Extraction of Metals

• Some metals occur in free state in nature (gold, silver, mercury).
• Most metals occur in combined form in the Earth's crust as compounds with different anions (oxides, sulphides, halides, silicates).
• The study of recovering metals from their ores is called metallurgy.
• Common steps in metal extraction include crushing and pulverization, concentration, calcination or roasting, reduction, and purification.
• Different methods of reduction is used based on ore and metal type

Properties and Trends in Group One (The Alkali Metals)

• The Group 1 elements have low densities.
• The first ionization energies in this group are lower than those of any other group.
• The atoms are very large, hence outer electrons are weakly held.
• Upon descending the group, the atomic size and reactivity generally increase, while ionization and electronegativity values generally decrease.
• The elements typically form ions with a positive (+1) charge.
• Generally glow with characteristic colors when placed in a flame (I.e., lithium is crimson, sodium is intense yellow, potassium is lilac, rubidium is red-violet, and caesium is blue).

Properties and Trends in Group Two (The Alkaline Earth Metals)

• Elements in this group are silver and soft.
• Each alkaline earth metal has two valence electrons.
• The reactivity increases on descending the group.
• Beryllium displays some deviation from the general trends observed in Group 2. This is due to its small size and high charge density. It is more prone to forming covalent compounds rather than ionic ones compared to the other Group 2 elements.
• The oxides and hydroxides in this group are less basic than those of group 1: hence, their oxosalts (i.e. carbonates, sulphates, and nitrates) are less stable to heat compared to similar group 1 oxosalts.
• The solubility of the sulphates decreases down the group.

Properties and Trends in Group Four (The Carbon Family)

• Metallic properties increase down the group.
• The elements tend to adopt +4 and, in the heavier elements, +2 oxidation states. (The inert pair effect)
• The elements in this group are relatively unreactive, but their reactivities increase down the group.
• Carbon exists in several forms called allotropes (I.e. diamond and graphite)
• Inorganic carbon may come in the form of diamond as a transparent, isotropic crystal; it is the hardest natural-occurring material on earth
• Silicon is a crystalline semi-metal or metalloid.
• When Silicon is molten, it is extremely reactive with most metals.

Hybridization and Shapes of Simple Molecules

• Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals. This process creates hybrid orbitals with entirely different energy, shapes, etc.
• The process of hybridization gives insight into the shapes, or structures, of simple molecules. For example, in sp hybridization, one s orbital and one p orbital mix to produce two sp hybridized orbitals.
• Hybridization helps in explaining molecular bonding processes

Isotopes, Radioactive Decay and Nuclear Reactions

• A nuclide is a nucleus with a defined number of protons and neutrons.
• When a nuclide falls outside the stability plot, it is unstable and undergoes radioactive decay.
• Radioactive decay is the spontaneous disintegration of an unstable nucleus into a more stable nucleus. This process involves emitting particles like α, β and γ particles.
• Common ways of transmutation include fission for heavy nuclei and fusion for lighter nuclei.
• The study of the behavior of atomic nuclei and the changes that occur in their structures or composition are called nuclear chemistry.
• The different types of radiations (alpha; beta; gamma) differ in terms of energy, penetration power, and the barriers used to protect against them.
• Radioactive elements can be used in various ways like medical treatment, dating objects, and the like.

Detecting Radioactivity

• Geiger-Müller tubes are able to detect β and γ radiation as these radiations ionize atoms in the gas fill, thus creating an electrical current

Background Radiation

• Everyone is exposed to radiation from various sources: cosmic rays, natural radionuclides in building materials & certain foods

Effects of Radiation

• Radiation damage depends on intensity of radiation, type of radiation, and type of material being irradiated.
• Irradiated organisms can exhibit somatic or genetic effects

Radiation Protection

• Minimizing radiation dose can be achieved by shielding, distance, and time.

Test your knowledge on metallurgy and ore processing principles with this quiz. Explore questions about the extraction of metals, calcination, roasting, and reduction processes. Perfect for students studying chemistry or materials science.