A student has written the following answer to describe and explain the reactivity of group 1 metals. However, they've
made lots of mistakes. Can you correct them?
"As you go down group 1, reactivity decreases because it gets harder to gain an
Celectron lo the outer shell,
This is because as you go down group 1, the outer shell gets closer to the positive
nucleus, meaning that there is a weaker force of attraction between the nucleus
and the positive electrons on the inner shell,
There is also less electron shielding as you go down group 1, because there are
more inner shell electrons, which repel the outer shell electron,
All of these reasons mean that as you go down group 1 the outer shell electron is
harder to lose

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.