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1

Since both are metaloids, or semiconductors, look for the criteria that define them. In particular, electronegativity or ionization energy are important.


0

Well the electronegativity increases across the period because the electrons are being added onto the same energy level,this increases the number of electrons of an atom,the increase of electrons of an atom also leads to increase in clear charge,in fact the nuclear charge increases more,this leads to attraction of electrons by the nuclear charge,hence ...


2

This is about the charges of polyatomic ions, determined by the number of valence electrons (i.e. group number in the periodic table) brought by all the atoms in the ion: If the polyatomic ion contains an odd number of atoms from elements with odd atomic number the charge of the polyatomic ion is odd. Otherwise the charge is even. The most common charges ...


2

La and Ac have $d^1$ electrons in their valence shells, rather than $f^1$ electrons. The long table you found looks like that for a several reasons. The trends going down Sc-Y-La are like those seen in groups 1 and 2. The trend going down Sc-Y-Lu is like that of groups 4 to about 10. Since lanthanide chemistry is basically that of trivalent alkali or ...


0

The word lanthanide means "like lanthanum". So it originally referred to Ce to Lu. Since La and the lanthanides share a lot of properties it became lazy practice to refer to all 15 elements as the lanthanides. That was unfortunate since it's resulted in the lanthanide contraction being associated with all 15 Ln, whereas it actually starts at Ce and finishes ...


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