Why is Potassium and Bromide KBr?
Why does Br not follow 2n2?
Br = 35 electrons, 2,8,18,7 why does the shell not fill to 32 and is happy with one of Potassium electrons.
Thank you kindly.
a. Br does follow 2N^2
b. There aren't enough electrons to fill it with more than 7.
The first shell is full with 2, the second with 8 and the third with 18. That used up 28 and you have only 7 more electrons (35-28 = 7) so you place 7 electrons in the 4th shell. You don't have any more electrons to add to make it go to 32.
The chemical formula for potassium bromide is KBr because potassium (K) has a positive charge of +1 and bromide (Br) has a negative charge of -1. In ionic compounds, the charges of the elements combine in such a way that the overall charge of the compound is zero.
Now, let's address your second question. The electron configuration of bromine (Br) is written as 2,8,18,7. The electron configuration describes the arrangement of electrons in different energy levels or orbitals around an atom's nucleus. According to the Aufbau principle, electrons fill the orbitals from the lowest energy level to the highest energy level.
In the case of bromine, the first two energy levels (1s and 2s) are filled, and then electrons start to fill the 2p orbital. The 2p orbital can accommodate a maximum of six electrons, but in the case of bromine, it has only seven electrons. This discrepancy is due to the fact that bromine's atomic number is 35, so it has 35 electrons to accommodate in its orbitals.
The reason the 2p orbital is not completely filled with six electrons is because of the tendency for atoms to gain or lose electrons in order to achieve a stable electron configuration. When bromine forms an ion, it gains one electron from another element to attain a stable outer electron configuration of 2,8,18,8. By gaining an additional electron, bromine achieves a full 2p orbital and becomes negatively charged, forming a bromide ion with a charge of -1.
On the other hand, potassium (K) has a positive charge of +1. It has the electron configuration of 2,8,8,1. The outermost energy level of potassium, which is the fourth energy level, has only one electron. Potassium tends to lose this one electron to achieve a stable electron configuration of 2,8,8. By losing an electron, potassium achieves a full 3s orbital and becomes positively charged, forming a potassium ion with a charge of +1.
In an ionic compound like potassium bromide (KBr), the two ions, K+ and Br-, combine in a one-to-one ratio to form a neutral compound. The positive charge of potassium cancels out the negative charge of bromide, resulting in a stable and electrically neutral compound.
In summary, the chemical formula KBr reflects the ionic nature of potassium bromide, where potassium loses one electron to become K+ and bromine gains one electron to become Br-. The electron configuration of bromine does not follow the pattern of 2n^2 because the stability of the atom is achieved by gaining or losing electrons to attain a full outer electron configuration.