Answer:
Option B. +3 and +6
Explanation:
<em>Zeff</em> = <em>z - s</em>
where <em>z</em> is the atomic number, <em>s</em> is the number of shielding(non-valence) electrons
For Boron, electronic configuration is 1s²2s³.
z = 5, s = 2
Zeff = 5 - 2 = +3
For Oxygen, electronic configuration is 1s²2s²2p⁴
z = 8, s = 2
Zeff = 8 - 2 = +6
Answer: 15.433704
Use the periodic table to check the atomic mass, this is the number of grams per mole → 1 mole of Aluminum is 26.982 g
From the relative atomic mass of each element, it is possible to determine each element's molar mass by multiplying the molar mass constant (1 g/mol) by the atomic weight of that particular element. The molar mass value can be used as a conversion factor to facilitate mass-to-mole and mole-to-mass conversions.
Answer:
It's a soft metal, reactive and with a low melting point, with a relative density of 0,97 at 20ºC (68ºF)
