The atoms of which element will typically form ions

Ions are electrically charged particles, meaning, that whenever any type of atom loses or gains electrons it is forming a new type of structure, or ion.

Metal atoms form postive ions, Non-Metals form negative ions.

The strongest type of bond that can occur between two ions, when they are oppositely charged, are Ionic Bonds. The most commonly known ionic bond is seen in Sodium and Chlorine, which when combined give us NaCl or Sodium Chlorine, aka Salt.

+1 charge = Group 1, Metals

+2 charge = Group 2, Alkali Metals

-1 charge = Group 17, Halogens

Provided is a periodic table marked with the charges for each group.

the answer is option a.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.