Q:

On the periodic table, what are the rows called?

A:

Quick Answer

The horizontal rows on the periodic table of the elements are called periods. Every element in a period has the same number of atomic orbitals. For instance, hydrogen and helium are in the first period, so they both have electrons in one orbital.

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Full Answer

The columns on the table divide the elements into groups with the same number of electrons in their outer shells. These electrons, called valence electrons, cause them to share chemical properties. For example, noble gases have full valence shells, so they are unreactive, and halogens, such as fluorine and chlorine, react vigorously with alkali metals, such as sodium and potassium.

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Related Questions

  • Q:

    Why was the periodic table invented?

    A:

    The periodic table was invented by chemist Dmitri Mendeleev to organize and compare elements and understand their relations with each other. Mendeleev created the periodic table between 1868 and 1870 while writing his book titled "The Principles of Chemistry." Initially, Mendeleev created the chart for his personal benefit, but others quickly discovered its value, leading to its immediate acceptance and use by fellow chemists upon publication.

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  • Q:

    What is the Periodic Table of the Elements?

    A:

    The periodic table of elements is a chemistry reference that lists elements by increasing atomic number, which typically correlates to their atomic masses. The atomic number increases from left to right as well as from top to bottom. Each of the rows on the table is a period.

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  • Q:

    What family does the element aluminum belong to?

    A:

    Aluminum belongs to the Boron family, which is group number 13 on the periodic table of elements. The other elements in the Boron family are the metals thallium, indium, gallium and the semi-metal boron. The element aluminum is a solid metal at room temperature that is assigned the period number 3 and atomic number 13 on the periodic table of elements.

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  • Q:

    How does Mendeleev's Periodic Table differ from the present one?

    A:

    Dmitri Mendeleev's periodic table featured elements arranged in accordance with their atomic mass, while the modern table has elements arranged according to periodic number. Mendeleev's periodic table also had the elements arranged vertically, whereas the modern table has them arranged horizontally.

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