Elements in the halogen group are

a. very reactive

b. have seven electrons in the outer shell

c. react to form salts

d. all of the above

Explain the fundamental steps of the scientific method.

A balanced reaction equation must have the same number of atoms of each element on both sides of the equation. The reaction C2H5OH+3O2→2CO2+3H2O represents the combustion of ethanol. Count the atoms of each element on both sides of the reaction.

2. Lithium-6 is 4% abundant and lithium-7 is 96% abundant. What is the average mass of lithium?

Which of the following characterizes the sodium-potassium pump? A) Sodium ions are pumped out of a cell against their gradient. B) Potassium ions are pumped into a cell against their gradient. C) The pump protein undergoes a conformational change.

Draw a single lewis structure for the phosphate ion (po43-), assuming that the phosphorus atom can expand its octet such that the formal charge on each of the atoms is minimized. include all formal charges and lone-pair electrons.

During which phase change does the arrangement of water molecules become more orderly A.) melting B.) subliming C.) boiling D.) condensing

What's the difference between Mixture and Solution?

Which describes the alkalaine solution? A) pH less than 7 B) pH equal to seven C) basic D) acidic

Limestone is primarily a crystal form of caco 3 . How many moles of oxygen are in a 1.25 mol sample of caco 3 ? Only include the numerical value in your answer. Do not include units.

The expression of 5522 km in scientific notation is