Questions

A cumulene is a hydrocarbon with three or more cumulative double bonds. They are analogous to allenes, only having a more extensive chain. The simplest molecule in this class is butatriene, which is also called simply cumulene.

The carbons on the ends are sp² hybridized, with a p-orbital for the 'second' bond in the double bond with their neighboring carbons.

They have those sp² orbitals overlapping with the s from the hydrogen, and they have a p overlapping in the pi bond with the neighboring carbon. They also have a sigma bond with the neighboring carbon I'll get to.

The middle carbons each have two pi bonds with their neighbors, leaving sp hybridiaztion for the rest. So they have sp/sp² with the end carbons, and sp/sp with each other. (And they also have p/p in the pi bonds).

All orbital overlappings in Cumuene are :

* s/sp²

* p/p

* sp/sp²

* sp/sp

ICMP means Internet Control Message Protocol and is always coupled with the IP protocol (There are 2 ICMP variants one for IPv4 and one for IPv6.) echo request and echo response are the two operation codes of ICMP used to implement ping.

Amino acids are organic compounds containing amine (-NH2) and carboxyl (-COOH) functional groups, along with a side chain (R group) specific to each amino acid.

Depending on the nature of the side chain groups, three classes of aminoacids can e distinguished:

1. Amino acids with H ond donor and acceptor groups.

Histidine, lysine, aspartic acid, threonine,...

2. Amino acids with donor grups only.

Arginine, tryptophan and cysteine.

3. Amino acids with acceptor groups only.

Asparagine and glutamine.

Dull means not sharp, not shining, not bright, ...

Hence, the given words are all that means the opposite of dull.

Rafael Nadal defeated Daniil Medvedev in the men's singles title at the 2019 US Open. It was Nadal's 19th Grand Slam singles title, and fourth US Open title.