Atomic Radius Flashcards
(10 cards)
What is atomic radius?
A measurement used to quantify the size of atoms, defined as the distance from the nucleus to the valence shell electrons.
How is atomic radius measured?
By halving the distance between the nuclei of two bonded atoms of the same element.
What unit is atomic radius measured in?
Picometres (pm), where 1 pm = 10^-12 m.
What is the atomic radius of a hydrogen atom in a hydrogen molecule (H2) given that the distance between the nuclei is 64 picometres?
32 picometres.
What trend occurs in atomic radii as you move down a group in the periodic table?
Atomic radii increase.
Why do atomic radii increase down a group?
The effective nuclear charge stays constant while the number of shells increases.
What trend occurs in atomic radii as you move left to right across a period?
Atomic radii decrease.
Why do atomic radii decrease across a period?
The number of occupied shells remains constant, but the effective nuclear charge increases, attracting valence electrons closer to the nucleus.
Fill in the blank: The distance from the nucleus to the valence shell electrons is called the _______.
[atomic radius]
True or False: Atomic radii are constant across all elements.
False.
