Multiple Choice
Which major element is a primary component of human bones (mainly as calcium phosphate in hydroxyapatite)?
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4. Atoms and Elements
Periodic Table: Classifications
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In the periodic table, what is a period?
A
A horizontal row of elements
B
A diagonal sequence of elements that share the same number of valence electrons
C
A classification for elements with similar chemical properties regardless of position
D
A vertical column of elements (a group)
Verified step by step guidance1
Understand that the periodic table is organized in rows and columns to display elements with similar properties in a structured way.
Recognize that a 'period' refers to a horizontal row of elements in the periodic table, where elements are arranged in order of increasing atomic number from left to right.
Note that elements in the same period have the same number of electron shells or energy levels, but different numbers of valence electrons.
Differentiate a period from a 'group,' which is a vertical column of elements sharing similar chemical properties and the same number of valence electrons.
Conclude that the correct definition of a period is a horizontal row of elements in the periodic table.
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