Which of these pairs of elements have the same number of valence electrons

phosphorus (P) and chlorine (Cl)

beryllium (Be) and calcium (Ca)

chlorine (Cl) and helium (He)

oxygen (O) and carbon (C)

Lead and silver chlorides are soluble in water. a. True b. False

Compare and contrast of cotton balls and pine cone

In most states, citizens register to vote with a A. county clerk B. poll worker C. district attorney D. post office clerk

A material that cannot be broken down farther by chemical means

The unstable isotope nickel-59 can be used to date rocks that contain it. Nickel-59 decays into the more stable cobalt-59. The nickel isotope has a half-life of 76,000 years.

How many grams of water form when 1.24 l of gas h2 at stp completely reacts with o2?

According to the following reaction, how many grams of hydrogen peroxide ( H 2 O 2 ) are necessary to form 0.182 moles oxygen gas? hydrogen peroxide ( H 2 O 2 ) (aq) → water (l) + oxygen (g)

Using the bohr model describe the changes in electrons energy and electron location when an atom changes from the ground state to an excited state.

Sally is making a model of gold for her chemistry class. She has foam balls for the protons, neutrons, and electrons. She has added 70 protons to her model so far. How many more protons does she need to add to complete her neutral atom of gold?

How many electrons are in an atoms of germanium