Dual coding theory has been applied to many cognitive phenomena including: mnemonics, problem-solving, concept learning and language. Dual coding theory accounts for the significance of spatial abilities in theories of intelligence (e.g., Guilford).
Properties. 1  Atomic Symbol: Cr. 2  Atomic Number: 24. 3  Atomic Mass: 51.996g/mol1.  Element Category: Transition 1  Metal. Density: 7.19g/cm3 at 20Â° C. Melting Point: 3465Â°F 1  (1907Â°C) Boiling Point: 4840Â°F (2671Â° C) Mohâs Hardness: 5.5.
The amorphous forms of selenium do not have specific melting points. Instead, they gradually become softer as they are heated. They may also change from one color and texture to another. The crystalline (metallic) form of selenium has a melting point of217Â°C (423Â°F) and a boiling point of 685Â°C (1,260Â°F).