How many variables should a scientist change at one time to have a good experiment?

What is the general valence-electron ground-state electron configuration for neutral alkaline earth metals?

What could J. J. Thomson conclude from his experiments? Atoms are mostly empty space. Most of the mass of the atom is concentrated in the center. Atoms must balance positive and negative particles. Atoms are indivisible.

How should the answer be reported using the correct number of significant figures?

The density of benzene at 15 ∘C∘C is 0.8787 g/mL. Calculate the mass of 0.1700 LL of benzene at this temperature. Express your answer using four significant figures.

Which compound is an Arrhenius base? (1) CH3OH (3) LiOH (2) CO2 (4) NO2

Write a net ionic equation to show that codeine, c18h21o3n, behaves as a bronsted-lowry base in water.

What is the name of the hybrid orbitals used by chlorine in clf3?

Which one is correct A. It allowed them to escape B. It allowed them to chase down C. It allowed them to reach food D. All of these

Boron is one position to the left of carbon on the periodic table. the atomic number of carbon is 6. given its position on the periodic table, what is the atomic number of boron

Actions of the non-valence electrons, diluting the force of the attraction between nucleus and valence electrons is called