A period is horizontal; the elements gain 1 proton for each space moving left to right.
A group is vertical; the elements in each group have the same number of electrons in the valence shell(outer orbital).
Initially, you should know that what the text describes is a test used to analyze and identify some metal ions in a compound. This is the principle behind it: first the ions are excited, by the heat of the flame, they absorb energy and the electrons are promoted to higher energy levels; after this, the electrons will fall back down to lower energy levels releasing energy as light. The flame color that is seen is related with the frequency of the light emitted.
Here is the text with the right words.
In this experiment, the metal cations in the solutions were initially in
the ground state. When placed in the flame, the metals then (absorbed)
energy as (heat). When this occurred,
electrons made transitions from (low) energy levels to (high)
energy levels. The metals were then in the (excited) state. The
electrons in these metals then made transitions from (high) energy
levels to (low) energy levels, resulting in the (emission) of energy as (EM radiation).
Periodic table? I don’t really know what you’re options are since there is no picture of the drop down or anything. If you can tell me what the options are, then I can answer more accurately. What you’re describing right now is the periodic table.
Answer:
<u><em>neurons</em></u>
Explanation:
The long-axoned cells, called principal neurons, transmit information over long distances from one brain region to another (Sheperd,1979). Principal neurons provide the pathways of communication within the nervous system.