np3 pipe np4
- non pressure pipe class np3 -np4 is used for heavy duty load
is used for medium duty load
It is Reinforced Concrete, Heavy Duty, Non-pressure Pipes.
The general electronic configuration of p block elements is ns2 np1-6. This means that the outermost electron shell of p block elements contains electrons in either the np1, np2, np3, np4, np5, or np6 orbitals.
The element with a valence electron configuration of ns2 np4 is sulfur (S). Since it needs to gain 2 electrons to achieve a stable electron configuration, it is most likely to form an ion with a charge of -2.
Big Pit is South West Wales, here is the address:- Big Pit National Coal Museum Blaenavon Wales NP4 9XP
In groups 13 through 18, valence electrons may be in the s, p, and d sublevels. Group 13 elements have valence electrons in the s and p sublevels, while group 14-18 elements may also have valence electrons in the d sublevel in addition to s and p sublevels.
For main group chemistry, the trend followed would be as such, where "n" is the valence orbital: ns1 = group 1 ns2 = group 2 ns2 np1 = group 3 (also called group 13) ns2 np2 = group 4 (also called group 14) ns2 np3 = group 5 (also called group 15) ns2 np4 = group 6 (also called group 16) ns2 np5 = group 7 (also called group 17) ns2 np6 = group 8 (also called group 18) This rule can only be successfully applied to main group chemistry, the D and F blocks (transition metals, lanthanides and actinides) do not follow this.
Atoms of elements in Groups 13-18 have 10 fewer valence electrons than their groups numbers.However , helium atoms have only 2 valence electrons.