7. Which trend is observed as the first four elements in Group 17 on the Periodic Table are considered in order of increasing atomic number?*
O (1) Electronegativity decreases.
(2) First ionization energy increases.
(3) The number of valence electrons increases.
(4) The number of electron shells decreases.

Which of these best describes an ionic bond?

Write the empirical chemical formula of calcium with a mass percent of 38.8, phosphorus with a mass percent of 20.0, and oxygen with a mass percent of 41.3.

Imagine if during the cathode ray experiment, the size of the particles of the ray was the same as the size of the atom forming the cathode. which other model or scientific observation would have also been supported? 1. this would support dalton's postulates that proposed the atoms are indivisible because no small particles are involved. 2. this would support bohr's prediction about electrons moving in orbits having specific energy. 3. this would support bohr's prediction about electrons being randomly scattered around the nucleus in the atom. 4. this would support dalton's postulates that proposed that atoms combine in fixed whole number ratios to form compounds.