Search results
Results from the WOW.Com Content Network
The lanthanide contraction is the greater-than-expected decrease in atomic radii and ionic radii of the elements in the lanthanide series, from left to right. It is caused by the poor shielding effect of nuclear charge by the 4f electrons along with the expected periodic trend of increasing electronegativity and nuclear charge on moving from left to right.
The lanthanide contraction, i.e. the reduction in size of the Ln 3+ ion from La 3+ (103 pm) to Lu 3+ (86.1 pm), is often explained by the poor shielding of the 5s and 5p electrons by the 4f electrons.
The size of Ln 3+ ions regularly decreases with atomic number. According to Fajans' rules , decrease in size of Ln 3+ ions increases the covalent character and decreases the basic character between Ln 3+ and OH − ions in Ln(OH) 3 , to the point that Yb(OH) 3 and Lu(OH) 3 can dissolve with difficulty in hot concentrated NaOH.
A molecule, called adenosine triphosphate (ATP) which is produced by an intracellular structure called a mitochondrion, is then used, as a source of energy, to help move the myosin head, carrying the actin. As a result, the actin slides across the myosin filament shortening the muscle. This is called a power stroke.
The Na + /K +-ATPase, as well as effects of diffusion of the involved ions, are major mechanisms to maintain the resting potential across the membranes of animal cells.. The relatively static membrane potential of quiescent cells is called the resting membrane potential (or resting voltage), as opposed to the specific dynamic electrochemical phenomena called action potential and graded ...
A metal ion in aqueous solution or aqua ion is a cation, dissolved in water, of chemical formula [M(H 2 O) n] z+.The solvation number, n, determined by a variety of experimental methods is 4 for Li + and Be 2+ and 6 for most elements in periods 3 and 4 of the periodic table.
In condensed-matter physics, channelling (or channeling) is the process that constrains the path of a charged particle in a crystalline solid. [1] [2] [3]Many physical phenomena can occur when a charged particle is incident upon a solid target, e.g., elastic scattering, inelastic energy-loss processes, secondary-electron emission, electromagnetic radiation, nuclear reactions, etc.
Since the valence has already been accounted for above, the charge q A of each ion in the equation above, therefore, should be interpreted as +1 or -1 depending on the polarity of the ion. There is such a current associated with every type of ion that can cross the membrane; this is because each type of ion would require a distinct membrane ...