How big is an atom? A simple question maybe, but the answer is not at all straighforward. To a first approximation we can regard atoms as 'hard spheres', with an outer radius defined by the outer electron orbitals. However, even for atoms of the same type, atomic radii can differ, depending on the oxidation state, the type of bonding and - especially important in crystals - the local coordination environment.
- How To Find Atomic Number
- Sc Atomic Number 1
- Sc Atomic Number Symbol
- Atomic Number And Mass Number Worksheet
- Sc Atomic Number 9
How To Find Atomic Number
Take the humble carbon atom as an example: in most organic molecules a covalently-bonded carbon atom is around 1.5 Ångstroms in diameter (1 Ångstrom unit = 0.1 nanometres = 10-10 metres); but the same atom in an ionic crystal appears much smaller: around 0.6 Ångstroms. In the following article we'll explore a number of different sets of distinct atomic radius sizes, and later we'll see how you can make use of these 'preset' values with CrystalMaker.
Name: Scandium: Symbol: Sc: Atomic Number: 21: Atomic Mass: 44.95591 atomic mass units: Number of Protons: 21: Number of Neutrons: 24: Number of Electrons: 21. The first main transition series begins with either scandium (symbol Sc, atomic number 21) or titanium (symbol Ti, atomic number 22) and ends with zinc (symbol Zn, atomic number 30). The second series includes the elements yttrium (symbol Y, atomic number 39) to cadmium (symbol Cd, atomic number 48). Atomic Symbol Sc Uses Scandium metal is used in some aerospace applications. Scandum oxide (Sc2O3) is used in the manufacture of high-intensity electric lamps. Scandium iodide (ScI3) is used in lamps that produce light having a color closely matching natural sunlight. Atomic Number 21 Learn more about the atomic number.
Atomic mass of Scandium is 44.9559 u.
Atomic Radii
Atomic radii represent the sizes of isolated, electrically-neutral atoms, unaffected by bonding topologies. The general trend is that atomic sizes increase as one moves downwards in the Periodic Table of the Elements, as electrons fill outer electron shells. Atomic radii decrease, however, as one moves from left to right, across the Periodic Table. Although more electrons are being added to atoms, they are at similar distances to the nucleus; and the increasing nuclear charge 'pulls' the electron clouds inwards, making the atomic radii smaller.
Atomic radii are generally calculated, using self-consistent field functions. CrystalMaker uses Atomic radii data from two sources:
VFI Atomic Radii:
Vainshtein BK, Fridkin VM, Indenbom VL (1995) Structure of Crystals (3rd Edition). Springer Verlag, Berlin.CPK Atomic Radii:
Clementi E, Raimondi DL, Reinhardt WP (1963). Journal of Chemical Physics 38:2686-
Covalent Radii
The covalent radius of an atom can be determined by measuring bond lengths between pairs of covalently-bonded atoms: if the two atoms are of the same kind, then the covalent radius is simply one half of the bond length.
Whilst this is straightforward for some molecules such as Cl2 and O2, in other cases one has to infer the covalent radius by measuring bond distances to atoms whose radii are already known (e.g., a C--X bond, in which the radius of C is known).
CrystalMaker uses covalent radii listed on CrystalMaker-user Mark Winter's excellent Web Elements website.
Sc Atomic Number 1
Van-der-Waals Radii
Van-der-Waals radii are determined from the contact distances between unbonded atoms in touching molecules or atoms. CrystalMaker uses Van-der-Waals Radii data from:
Bondi A (1964) Journal of Physical Chemistry 68:441-
Atomic-Ionic Radii
These are the 'realistic' radii of atoms, measured from bond lengths in real crystals and molecules, and taking into account the fact that some atoms will be electrically charged. For example, the atomic-ionic radius of chlorine (Cl-) is larger than its atomic radius.
The bond length between atoms A and B is the sum of the atomic radii,
dAB = rA + rB
CrystalMaker uses Atomic-Ionic radii data from:
Slater JC (1964) Journal of Chemical Physics 39:3199-
Crystal Radii
Perhaps the most authoritative and highly-respected set of atomic radii are the 'Crystal' Radii published by Shannon and Prewitt (1969) - one of the most cited papers in all crystallography - with values later revised by Shannon (1976). These data, originally derived from studies of alkali halides, are appropriate for most inorganic structures, and provide the basis for CrystalMaker's default Element Table. The data are published in:
Shannon RD Prewitt CT (1969) Acta Crystallographica B25:925-946
Shannon RD (1976) Acta Crystallographica A23:751-761
The Colours of Atoms
Colour-coding atoms by element type is an important way of representing structural information. Of course, atoms don't have 'colour' in the conventional sense, but various conventions have been established in different disciplines.
Many organic chemists use the so-called CPK colour scheme These colours are derived from those of plastic spacefilling models developed by Corey, Pauling and (later improved on by) Kultun ('CPK').
Whilst the standard CPK colours are limited to the elements found in organic compounds, CrystalMaker's VFI Atomic Radii, CSD Default Radii and Shannon & Prewitt Crystal Radii Element Tables provide a more diverse range of contrasting colours.
Organic Structures Alert! CrystalMaker's default Element Table is the Shannon & Prewitt 'Crystal' radii, which is appropriate for most inorganic structures. When working with organic structures, one of the covalent or Van-der-Waals sets will be more appropriate.
Atomic Number of Scandium is 21.
Chemical symbol for Scandium is Sc. Number of protons in Scandium is 21. Atomic weight of Scandium is 44.955908 u or g/mol. Melting point of Scandium is 1539 °C and its the boiling point is 2832 °C.
» Boiling Point» Melting Point» Abundant» State at STP» Discovery YearAbout Scandium
Sc Atomic Number Symbol
Scandium is a rare metal known also as a transition metal. In its pure form, this metal is quite soft and reactive, especially with water and air. It is a carcinogen and quite a toxic element. Its name is derived from a Latin word meaning Scandinavia. Scandium is rather used for research since it is very rare and can be found only is a few rare types of minerals. As a metal, scandium has very low density, so it is used in alloys with other light metals like aluminum in aircraft industry, etc. Combined with mercury and iodine, scandium is used for producing bulbs.
Properties of Scandium Element
| Atomic Number (Z) | 21 |
|---|---|
| Atomic Symbol | Sc |
| Group | 3 |
| Period | 4 |
| Atomic Weight | 44.955908 u |
| Density | 2.989 g/cm3 |
| Melting Point (K) | 1814 K |
| Melting Point (℃) | 1539 °C |
| Boiling Point (K) | 3109 K |
| Boiling Point (℃) | 2832 °C |
| Heat Capacity | 0.568 J/g · K |
| Abundance | 22 mg/kg |
| State at STP | Solid |
| Occurrence | Primordial |
| Description | Transition metal |
| Electronegativity (Pauling) χ | 1.36 |
| Ionization Energy (eV) | 6.5615 |
| Atomic Radius | 160pm |
| Covalent Radius | 144pm |
| Valence Electrons | 2 |
| Year of Discovery | 1879 |
| Discoverer | Nilson |
What is the Boiling Point of Scandium?
Uea office 365. Scandium boiling point is 2832 °C. Boiling point of Scandium in Kelvin is 3109 K.
What is the Melting Point of Scandium?
Scandium melting point is 1539 °C. Melting point of Scandium in Kelvin is 1814 K.
How Abundant is Scandium?
Abundant value of Scandium is 22 mg/kg.
What is the State of Scandium at Standard Temperature and Pressure (STP)?
State of Scandium is Solid at standard temperature and pressure at 0℃ and one atmosphere pressure.
When was Scandium Discovered?
Atomic Number And Mass Number Worksheet
Scandium was discovered in 1879.
Sc Atomic Number 9