Answer key which elements puts 7 valence electrons into to 3rd energy level ring

When determining an element's identity, what is the most important subatomic part to examine? A) electrons B) neutrons C) valence electrons D) protons

The molar heat of vaporization for water is 10.79 kJ/mol. How much energy must be absorbed by 100 grams of water at 100 °C in order to convert it to steam at 100 °C?

The density of gold is approximately. 1785 g/L. What is the mass of a sample of helium that occupies 50.0 L of space? Round your answer to the correct number of significant figures. 1.00 g 9.00 g 50.0 g 280. g

Why is a kite flying in the sky an example of potential energy? A. The kite is constantly moving. B. The kite is being pushed by the winds. C. The kite is high above the ground. D. The kite is being pulled by a string.

A chemist measures the energy change? H during the following reaction: 2H2O (l) ?2H2 (g) + O2 (g) =? H572. kJ Is the reaction endothermic or exothermic? Does it absorb or release heat when 75.

Which is a pure substance A) mixture B) solution C) element

Samuel adds a teaspoon of salt to a glass of water. He notices that the song disappears. Samuel takes a sip to discover that the water taste salty. What kind of change has occurred?

How are the physical and chemical properties of atoms represented on the periodic table of elements

how do we know isotopes exist?

Is albinism a dominant or recessive trait