What is the electronica figuration of an element with atomic number 20

Answer with explanation:

The electronic configuration of an element is the representation of the arrangement of electrons present in it that are distributed among the orbital shells and sub-shells.

The element with atomic number 20 is Calcium and its electronic configuration will be as following:

The first two electrons of this element will go into the 1s orbital. Since 1s can only hold two electrons so the next 2 electrons will go into the 2s orbital.

The next six electrons will go into the 2p orbital. Since the p orbital can hold up to a maximum of six electrons, we will put six in the 2p orbital and then put the next two electrons in the 3s.

The 3s is now full so we will move to 3p and place the next six electrons. We now shift to the 4s orbital where we will place the remaining two electrons.

Therefore. the electronic configuration of Calcium will be

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

10 years is the answer