. Identify molecules of elements;
O2, NH3, He

Elements can be made of one atom, like He, or be elemental molecules, such as hydrogen (H2), oxygen (O2), chlorine (Cl2), ozone (O3), and sulfur (S8). Atoms are not drawn to scale. Some elements are monatomic, meaning they are made of a single (mon-) atom (-atomic) in their molecular form...

b) nuclear ive learned that in a pedtrodic table

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.