Which two periods have the same number of elements

Proper ion concentrations play an important role in cardiac function. which of the following would be a direct consequence of a deficiency in calcium ions?

Find the approximate atomic mass of a water molecule (h2o). give your answer in atomic mass units rounded to the nearest whole number.

How did the quantum mechanical model of the atom improve on bohr's atomic model?

when hydrochloric acid is dripped onto marble, bubbling is observed while dripping hydrochloric acid onto granite does not lead to bubbling. Based on these observations, what compound may be a component of marble but not granite?

Which two things drive the Global Ocean Conveyor Belt? temperature and density the moon and gravity salt and wind the moon and tides

The weighted average atomic mass of an element depends upon the a. relative abundance of protons in the element b. mass and relative abundance of each isotope of that element c. mass and relative abundance of each neutron of that element d.

What part of an atom do we change for isotopes

The Safe Drinking Water Act (SDWA) sets a limit for mercury-a toxin to the central nervous system-at 0.002 mg/L. Water suppliers must periodically test their water to ensure that mercury levels do not exceed 0.002 mg/L.

The smallest unit of an element is a blank

How many sodium atoms will create an ionic bond with sulfur?