Answer: Count only the electrons in the highest shell s and p orbitals when determining valence.
Explanation: I'm glad you asked this question. It is often not well explained. The term valence electrons is assigned to only the electrons in an element's highest energy level. These reside only in the s and p orbitals, and not the d or f, as I'll explain later. The s orbital can hold 2 electrons and the p can hold 6. Potassium, K, has an s orbital in its highest energy shell, 4. It contains only 1 electron, so it has a valency of 1.
Calcium, Ca, has 2 in its highest energy level: 4s^2, so it has a valency of 2. Moving to the right, the element scandium, Sc, add another electron, but it goes into the 3d orbital. 3d is in the 3rd energy shell, so it is not counted as a valence electron. Only after we move further right, to gallium, Ga, do we start adding electrons to the 4th energy level again - the 4p orbitals can accept up to 6 electrons. Ga has 3 valence electrons - 2 in the 4s and 1 in the 4p. Oxygen has 2 in the 2s and 4 in the 4p orbitals, for a total of 6. It is close to having a comple outer shell (2 in the 2s and 6 in the 2p). Just 2 more electrons would fill both the 2s and 2p orbitals for a total of 8 valence electrons, a stable configuration (the same configuration as thje stable gas Neon).
Hello!
Use the equation d = s · t where:
s = speed
t = time
d = distance
Plug in the given distance and speed:
20 = 12 ·t
Divide both side by 12 to isolate for t:
20/12 = t
Simplify:
5 / 3 = t
Therefore, it took 5/3 hours to bike. We can convert this to minutes if necessary:
5/3 · 60 min (in one hour) = (60 · 5) / 3 = 100 min.
Answer:
Explanation:
When metal and nonmetal ions form ionic bonds, their total electrical charges must balance each other exactly (as in, add up to zero). In order to write a correct formula, you must know the ion charges of all the atoms involved.
Answer:
The amount of water on the Earth is constant, or nearly so. Actually, the amount is increasing ever so slightly due to volcanic eruptions expelling water vapor into the atmosphere, but, for all practical purposes, the amount of water (as a gas, liquid and as snow and ice) can be considered to be constant.
Explanation:
Well thats because things changed in science. Newtons law of gravity (which was all things that come up must come down) evolved once scientist figured out that in space things float around. Science always evolves weather it's in a year or a day, but if your asking about HOW it evolved, thats something different. Hope I'm helping you!