Period 3 elements Flashcards
What is atomic radius?
the distance between the nucleus and the outermost electrons of an atom
What does atomic radius do across the period? and why does it do this?
Decreases
-the nuclear charge is increasing meaning there’s greater attraction between the nucleus and out electrons drawing them closer together
What is ionic radius
the distance between the nucleus and the outermost electron of an ion
What does ionic radius do for cations across a period? and why?
It decreases
-they have lost their valency electron which causes them to be smaller hence less shielding effect
-as nuclear charge increases the electrostatic attraction also increases
What does ionic radius do for anions across a period? and why?
increases
-they are gaining electrons and are larger so the distance between the nucleus and the outermost electron continues increasing cause weaker electrostatic attraction towards the nucleus
What is the trend in melting and boiling points across period 3?
-From Na to Al the m.p and b.p increases due to an increase in metallic bonding
(there’s a stronger electrostatic attraction between the metal cations and the delocalised electrons)
-Si has the highest m.p and b.p because it is a macromolecule that has a giant covalent lattice structure
(more energy is required to break the bonds)
-From P4 to Cl2 the m.p and b.p is dependant on the intermolecular forces/ VDW forces
(the greater the surface area the more the Vdw forces, so S8 has the higher m.p and b.p)
the covalent bonds within the molecules are strong, however, between the molecules, there are only weak instantaneous dipole-induced dipole forces
What is the trend for electrical conductivity across period 3?
From Na to Al it increases and then decreases for other elements
(it increases because the number of delocalised electrons increases so more carriers available for electricity)
What is the equation of sodium oxide and what products are produced?
2Na (s) + 1/2O2 (g) ——> Na2O (s)
bright yellow flame
white solid formed
What is the equation of magnesium oxide and what products are produced
2Mg (s) + O2 (g) ——> 2MgO (s)
bright white flame
white solid formed
What is the equation of Aluminium oxide and what products are produced
4Al (s) + 3O2 (g) ——> 2Al2O3 (s)
bright white flame
white solid formed
What is the equation of Silicon oxide and what products are produced
Si (s) + O2 (g) ——–> SiO2 (s)
bright White sparkles
white solid formed
What is the equation of Phosphorus oxide and what products are produced
4P (s) + 5O2 (g) ——-> P4O10 (s)
yellow or white flame
white clouds formed
What is the equation of Sulphur oxide and what products are produced
S (s) + O2 (g) ——-> SO2 (s)
blue flame
toxic fumes produced
What is the reaction of sodium with chlorine?
2Na + Cl2 ——-> 2NaCl
bright orange flame
white solid formed
vigorous reaction
What is the reaction of Magnesium with chlorine?
Mg + Cl2 ——> MgCl2
bright white flame
white solid formed
