7.1: The periodic table

As of 2014, how many elements are in the periodic table? And how many groups and periods are they sorted into.

1) there are 114 elements. 2) arranged in seven periods and 18 groups.

What does each element in a group have?

atoms with the same number of outer-shell electrons and similar properties

What can the elements in the periodic table be divided into?

blocks (s, p, d, and f), corresponding to their highest energy sub-shell

How did Mendeleev predict properties of the missing elements of the Periodic table?

from group trends

What is the term describing how the elements are arranged in vertical columns?

groups

How did Mendeleev line up the elements in groups?

he lined up the elements in groups with similar properties

What would Mendeleev do if the group properties did not fit?

he swapped elements around and left gaps, assuming that atomic mass measurements were incorrect and that some elements were yet to be discovered

Horizontally, how are the elements arranged in order of?

increasing atomic number. so each successive element has atoms with one extra proton.

How many elements were known when Mendeleev arranged them in order of atomic mass?

just over 60 elements

Across each period, what is the term for the repeating trend in properties of the elements?

periodicity

What is the term describing how the elements are arranged in horizontal rows?

periods

Across Period 2, what sub-shells fill?

the 2s sub-shell fills with two electrons, followed by the 2p sub-shell with six electrons

Across Period 4, what sub-shells fill?

the 3d sub-shell fills with ten electrons. from the n=4 shell, only the 4s and 4p sub-shells are occupied

Across Period 3, what sub-shells fill?

the 3s sub-shell fills with two electrons, followed by the 3p sub-shell with six electrons

Describe the different blocks of the Periodic table

the extreme left of the Periodic table is the s block, the right is the p block, the middle is the d block, and the f block is the bottom of the table

What does the number of the period show?

the number of the highest energy electron shell in an element's atoms

What is the most obvious periodicity in properties?

the trend from metals to non-metals

What does the arrangement, pattern, and shape of the periodic table reveal?

trends among the elements

Until what point did Mendeleev not reveal the real reason order for the Periodic Table?

until the early 1900s - when protons were discovered