Trends in Atomic Radii (Leaving Cert Chemistry): Flashcards
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Definition of covalent radius
Definition of covalent radius
Half the distance between nuclei of 2 identical atoms joined by a single covalent bond
Covalent radius of hydrogen (from )
Covalent radius of hydrogen (from )
0.037 nm
Atomic radius trend across a period (left to right)
Atomic radius trend across a period (left to right)
Decreases
Why radius decreases across period (charge factor)
Why radius decreases across period (charge factor)
Increased nuclear charge pulls electrons closer
Why radius decreases across period (shell factor)
Why radius decreases across period (shell factor)
Same energy level, greater effective nuclear charge
Atomic radius trend down a group (top to bottom)
Atomic radius trend down a group (top to bottom)
Increases
Why radius increases down group (shell factor)
Why radius increases down group (shell factor)
Additional electron shells further from nucleus
Why radius increases down group (screening)
Why radius increases down group (screening)
Screening effect reduces effective nuclear charge
Definition of screening effect
Definition of screening effect
Inner electrons shield outer electrons from nuclear charge
How screening effect changes down a group
How screening effect changes down a group
Becomes stronger (more inner shells)
Three key factors affecting atomic radius
Three key factors affecting atomic radius
Nuclear charge, energy levels, screening effect
Noble gases and covalent radii
Noble gases and covalent radii
Don't have values; rarely form covalent bonds
Effect of more protons on atomic radius
Effect of more protons on atomic radius
Stronger attraction, smaller radius
Effect of more electron shells on atomic radius
Effect of more electron shells on atomic radius
Electrons further out, larger radius