1 2 the periodic table

Periodic refers to patterns that emerge at regular intervals in the periodic table when the elements are sorted by mass.

Dmitri Mendeleev created the first draft of the periodic table in 1869.

False. Mendeleev used properties of the elements (and their compounds) to arrange them vertically and atomic mass to arrange them horizontally.

False. Mendeleev left gaps in the table that he thought would best be filled by elements that had not yet been discovered.

False. Mendeleev arranged elements by increasing atomic mass but also considered chemical properties. An example of this is switching tellurium and iodine because iodine fitted better with the other halogen elements, even though tellurium is heavier.

Mendeleev's decision to leave gaps in the table, rather than forcing elements to fit, allowed him to predict the existence and properties of then-unknown elements.

True. Elements with similar properties are arranged in the same group on the Periodic Table.

A group is a vertical column on the Periodic Table.

Periods indicate the number of electron shells in an atom.

Elements are arranged by increasing atomic number in periods and groups.

True. Each element has one proton more than the previous one.

A period is a horizontal row on the Periodic Table.

Elements are arranged by increasing atomic number so that they end up in columns with similar properties.

Groups indicate the number of outer electrons in an atom.

True. Most elements are metals.

Non-metals are generally located on the right-hand side of the Periodic Table.

An electronic configuration is the arrangement of electrons in shells.

True. Electrons occupy the shell closest to the nucleus first.

The first shell can hold a maximum of 2 electrons.

The group gives the number of outer electrons.

True. Chlorine has 3 shells of electrons.

The electronic configuration of sulfur is 2, 8, 6.

The last number in an electronic configuration represents the number of outer electrons.

The second and third shells can each hold a maximum of 8 electrons.

In terms of electrons, other words for shell include:

False. Most elements do not have full outer shells of electrons.

True. Atoms are more stable if they can completely fill their outer shell with electrons.

The electronic configuration of carbon is 2.4.

False. The number of notations in the electronic configuration shows the period that the element is in, indicating the number of occupied shells.

The element with the electronic configuration 2.8.1 is sodium.

Silicon has 3 electron shells and 4 outer electrons .

True. Helium has only one shell of electrons - the first and innermost shell, which holds only 2 electrons.

True. Noble gases have full outer shells of electrons.

Neon's electronic configuration is 2. 8.