Which list includes elements with the most similar chemical properties? 1.br, ga, hg 2. cr, pb, xe 3. o, s, se 4. n, o, f

The correct answer is Option 3.

Explanation:

Elements are distributed in 7 Periods and 18 groups in a periodic table.

Elements which belong to same group show similar chemical properties because of the same number of valence electrons.

For the given options:

Option 1: Br, Ga and Hg

Bromine is present in Group 17, Gallium is present in 13 and Mercury is present in Group 12.

As, all the three elements belong to different groups. So, they do not show similar chemical properties.

Chromium is present in Group 6, Lead is present in Group 14 and Xenon is present in Group 18.

As, all the three elements belong to different groups. So, they do not show similar chemical properties.

Oxygen, Sulfur and Selenium are present in Group 16.

As, all the three elements belong to same group. So, they will show similar chemical properties.

Nitrogen is present in Group 15, Oxygen is present in Group 16 and Fluorine is preset in Group 17.

As, all the three elements belong to different groups. So, they do not show similar chemical properties.

Hence, the correct answer is Option 3.

catya that's not even a b or c

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.