Explain how the understanding of atomic emission led to development of the atomic theory.

Identify which of the following statements are true. Check all that apply. Check all that apply. Ionization energies are always negative quantities. The third ionization energy is the energy needed to ionize three electrons from a neutral atom.

Calcium (atomic number 20) has electron configuration 1s2,2s2,2p6,3s2,3p6,4s2. The atomic number of scandium is 21. Which orbital does the 21st electron enter? a. 3d b. 4p c. 4d d. 4f

Which two statements are true about a system? A) all systems are made by humans B) a system is a group of objects analyzed as one unit C) energy they moves across system boundaries is conserved D) there's only one way to define the boundaries of a

In the solubility lab, what did you change the temperature of

Which of the following has can make 3 bonds? A-sodium (Na) B-Neon (Ne) C-Oxygen (O) D-Nitrogen (N)

A battery is constructed based on the oxidation of magnesium and the reduction of cu2+. the initial concentrations of mg2 + and cu2 + are 1.2*10-4 m and 1.44 m, respectively, in 1.0-liter half-cells. how long can the battery deliver 5.

A buffer solution is made that is 0.417 M in and 0.417 M in. If for is, what is the pH of the buffer solution? pH = Write the net ionic equation for the reaction that occurs when 0.120 mol is added to 1.00 L of the buffer solution.

BaCl2 (aq) + AgNO3 (aq) → Express your answer as a chemical equation. Enter noreaction if no precipitate is formed.

Make a list of physical changes and chemical changes that you observe or see effects of in the school

Which equation obeys the law of conservation of mass? H2 (g) + O2 (g) → H2O (g) H2 (g) + O2 (g) → H2O (g) + 4He (g) 2H2 (g) + O2 (g) → 2H2O (g) H2 (g) → H2O (g) H2 (g) + O2 (g) → 2H2O (g)