Which scientist proposed the model of an atom as a nucleus surrounded by electrons

A pharmacist has a prescription for 30 ml of an eye drop that is to contain benzalkonium chloride 1:750 as a preservative. on the shelf the pharmacist finds 17% benzalkonium chloride.

Orbitals are defined by which term? • spin direction • energy level • composition • number of electrons

Why will external fluid flow into a plant cell? because the external water concentration is greater because the external water concentration is less because the external salt concentration is greater because the external salt concentration is less?

As the elements of Group 17 are considered in order of increasing atomic number, there is an increase in (1) atomic radius (2) electronegativity (3) first ionization energy (4) number of electrons in the first shell

Explain why it is important that there be no gaps around the edges of the filter paper during a vacuum filtration.

What is the biggest difference between an exothermic and endothermic process? A. The direction of energy flow. B. The amount of energy transferred. C. The type of energy being transferred. D. The speed with which energy is transferred.

The mass of 1 mol of chromium (atomic mass 51.996 amu) is

Which of the following elements will tend to form a cation? A. Oxygen B. Nitrogen C. Sulfur D. Lead E. All of the Above

Is pure orange juice a solution or a suspension

If a catalyst is used in a reaction: a. the energy of activation increases. b. the reaction rate does not change. c. the reaction rate increases. d. the equilibrium shifts.