Atomic Theory and Structure The Periodic Table of Elements: Origins and meaning by Anthony Carpi, Ph.D. Reading Quiz Teach with this Dmitri Mendeleev organized the chemical elements: by number of electrons by increasing atomic weight and similar properties by increasing atomic number and similar properties in alphabetical order The elements in the present periodic table are arranged according to their: atomic masses mass number atomic number atomic weight A vertical column in the periodic table is called a: valence branch group period A horizontal row in the periodic table is called a: shells branch group period The majority of the elements in the periodic table are: noble gases nonmetals metalloids metals What does Bohr's theory state? Electrons occur around the nucleus in electron shells that have a limited capacity Electrons are located randomly around an atom's nucleus Electrons occur in shells of unlimited capacity Electrons don't occur at all in atoms What is the capacity of the first electron shell? sixteen eight three two Which of the following is the electron configuration for carbon: C )2e- )8e- )2e- C )2e- )6e- C )2e- )4e- Ca )2e- )8e- )2e- Elements in the some group have: similar symbols the same number of neutrons the same number of valence electrons the same number of electrons Elements in the same period have: the same number of neutrons gradually changing properties similar symbols identical chemical properties Which element is classified as metalloid? Ca Cl Si Zn How many valence electrons does calcium have? one two eight twenty How many valence electrons does boron have? one two three four Score Quiz