Electron Configuration and Valence Electrons. The electrons in an atom fill up its atomic orbitals according to the Aufbau Principle; Aufbau, in German, means building up..ach element has a number of valence electrons equal to its group number on the Periodic Table. This table illustrates a number of interesting, and complicating, features of electron configuration. Figure %: The periodicity of valence electrons. First, as electrons become higher in energy, a shift takes place.
I took the pregnancy test early at 2 & 3 weeks pregnant, and it came up negative twice. Yet I could feel something was different about my body, even though I had my cycle it fell short a few days, and was very light. Afterwards, I had breast tenderness, and dizziness.
This is known as a false-negative â and it's much more likely to occur than is a false-positive. You might get a false-negative if you: Take the test too early. The earlier after a missed period that you take a home pregnancy test, the harder it is for the test to detect HCG. For the most accurate results, take the test one week after a missed period â when the level of HCG in your urine is most likely to be detectable.