The Periodic Table Flashcards
How are elements arranged in the periodic table?
In order of atomic (proton) number, with similar properties in columns known as groups.
Why is it called a periodic table?
Similar properties occur at regular intervals.
What do elements in the same group have in common?
They have the same number of electrons in their outer shell, resulting in similar chemical properties.
What should students be able to explain about the periodic table?
How an element’s position relates to the arrangement of electrons and its atomic number.
What can students predict from the positions of elements in the periodic table?
Possible reactions and probable reactivity.
How did scientists attempt to classify elements before the discovery of protons, neutrons, and electrons?
By arranging them in order of atomic weights.
How did Mendeleev address problems in early periodic tables?
Left gaps for undiscovered elements and changed order based on atomic weights.
What filled the gaps left by Mendeleev, and why was the order based on atomic weights not always correct?
Elements with properties predicted by Mendeleev were discovered; isotopes explained discrepancies.
What should students be able to describe?
The steps in the development of the periodic table.
