Describe the trend in atomic radius as the atomic number increases down a group.

Henry moseley used x-ray experiments to determine the atomic number of elements. how did his discovery contribute to the development of the periodic table? a.it confirmed that elements should be arranged in strict order of increasing atomic mass. b.it led to elements with similar atomic numbers being grouped together. c.it allowed the elements to be placed in strict order of increasing atomic number. d.it showed that the way mendeleev grouped elements together was completely wrong.

Me with this homework my gradebook are closing today so

Select the correct answer. which statement best explains the octet rule? a. atoms gain, lose, or share electrons to achieve a full valence shell. b. compounds always consist of eight electrons. c. molecules always consist of eight atoms. d. all atoms require eight electrons to form bonds.