Chemistry Assessments

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Ionization energy generally increases across a period from left to right, as the atomic number increases and electrons are added to the same energy level while experiencing greater nuclear charge.

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Electronegativity is a measure of the tendency of an atom to attract a shared pair of electrons (or electron density) towards itself in a chemical bond.

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Silicon is a semi-metal (metalloid) that uniquely has its electrical conductivity increase with temperature, making it valuable in electronic devices and semiconductors.

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The atomic radius generally increases down a group in the periodic table due to the addition of more electron shells.

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Halogens are highly reactive elements, particularly with alkali metals, with which they form ionic compounds like table salt (sodium chloride).

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Alkali metals refer to the elements in Group 1 of the periodic table, known for being highly reactive and forming strongly alkaline hydroxides with water.

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Dmitri Mendeleev’s periodic table was significant for arranging elements in order of increasing atomic mass and grouping them by similar chemical properties, predicting the properties of elements not yet discovered.

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The electron configuration of an element describes the distribution of electrons in the atomic orbitals around the nucleus of an atom.

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Tungsten is used in lightbulb filaments because of its very high melting point, which allows it to glow brightly without melting.

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Metalloids are elements with properties intermediate between those of metals and nonmetals, often found along the "staircase" line on the periodic table.