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Why is there a significant difference between the radii of first and second row transition metals, where as no difference (or even a decrease) is observed between the second and third rows?

The answer stems from the lanthanide (or lanthanoid) contraction. In more detail, there is a steady decrease in the radii of atoms from Lanthanum through to Lutetium, despite the associated increase in the a...
IB
Answered by Ioannis B. • Chemistry tutor
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Define and then compare the periodic table trends (atomic radius, electronegativity, ionization energy, electron affinity) for Lithium (Li) and Sodium (Na).

The Atomic radius of an atom represents its atomic size. More specifically, it refers to the half-distance between the two nuclei of two adjacent atoms of the same element. In the periodic table, across a pe...
DA
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Use the following information: [[[[2H2(g) + O2(g) → 2H2O(l) ∆H = −572 kJ mol−1]]]] [[[[2H2(g) + O2(g) → 2H2O(g) ∆H = −484 kJ mol−1]]]] to calculate the enthalpy change for the process: H2O(g) → H2O(l)

Well the method I use for calculations in thermochemistry is a little different from the textbooks but is far easier to understand. I would approach this question by drawing out the chemical equations in a p...
LB
Answered by Louis B. • Chemistry tutor
10013 Views

What is an acid-base titration?

A titration is way to find an unknown concentration of a sample through a chemical reaction. The most common titration involves an acid and base to react. In order to set our experiment a standard is needed,...
GZ
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Using the VSEPR theory, predict the shape of CCl4 and its approximate bond angles.

Draw out the lewis structure of CCl4 by counting the number of valence electrons on each atom. C=4, Cl=7 therefore total valence electrons is 4+(7x4)=32 and total valence electron pairs is 16. 2. Determine t...
AM
Answered by Amy M. • Chemistry tutor
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