The subatomic particles that play the key role in determine the properties of an element electrons

Which of the precautions listed below is the most effective action to take in guarding against this hazard

5. How does the abundance of isotopes of an element relate to its average atomic mass?

In an exothermic reaction at equilibrium, what is the effect of lowering the temperature? A. The reaction makes more products. B. The reaction makes more reactants. C. The reaction is unchanged.

Explain why a cool flame is important in heating a solution to dryness

Which pair are classified as chemical substances? Pick two. elements, mixtures, compounds, solutions.

A 10 pound block of lead-210 has a half-life of 22 years. What percentage of the block still contains lead-210 after 60 years? 1.5% 15% 77% 27%

Combined gas law problem: a balloon is filled with 500.0 mL of helium at a temperature of 27 degrees Celsius and 755 mmHg. As the balloon rises in the atmosphere, the pressure and temperature drop.

1. What hypothesis could you propose about the relationship between the position of a type of atom in a molecule and the number of bonds that the atom forms? Explain your thinking.

The molality of a solution is a measure of - A - moles of solute per kilogram of solution B - moles of solute per liter of solution C - moles of solute per kilogram of solvent D - moles of solute per liter of solvent

Which technology has allowed for exploration beyond our solar system? A) space probe B) space station C) space shuttle D) space observatory