Atom x has an atomic number of 19 and has a mass number of 39. the number of protons in atom x is equal to

Selenium is a semiconductor used in photocopying machines. what type of semiconductor would be formed if a small amount of gallium impurity is added to pure selenium?

Once primers bind, what occurs next

Two of the disadvantages of using chemical agents for terrorist activity are that production and deployment are hazardous to terrorists and: select one: require large quantities require military training need a specific date require a lethal dose

When a counterfeit detection pen is used on an authentic bill, what color does it turn? a. Pale blue b. Pale yellow c. Blue-black d. Pale pink

How are fossil fuels formed? A. Volcanoes erupt, bringing up energy from underground. B. Plants and animals decompose underground. C. Fossils combust and release petroleum D. The sun sends energy to Earth.

Electric force is an A. attraction and repulsion between protons and electrons . B. attraction and repulsion between protons and neutrons. C. attraction and repulsion between neutrons and electrons.

A salt crystal has a mass of 0.18 mg. how many nacl formula units does it contain?

Which of the following is easist to accelerate? A. bowling ball B. tennis ball C. golf ball D. ping pong ball

Fish need at least 4 ppm dissolved o2 for survival. part a what is this concentration in mol/l?

How does a runoff get polluted.