They work by lowering the activation energy
Visual representation of covalent bonding indicating the valence shell electrons in the molecule, lines represents the shared pair of electron and pair of electrons that are not involved in bonding are represented as dots(lone pairs) are known as Lewis structures.
Compound formation takes place in order to complete the octet of each element that is according to octet rule, each atom forms bond with other atom in order to complete their octet that is to get eight electrons in its valence shell and attain stability.
An organic compound of the form 
is known as ketene.
The given ketene is 
.
The number of valence electron of:
The number of valence electrons in = 
2 electrons are involved in each single bond between carbon and hydrogen and 4 electrons are involved in each double bond formed between carbon-carbon and carbon-oxygen. Hence, the total number of electrons involved in bond formation are 12 and rest 2 pair of electrons are present on oxygen as lone pair of electrons.
Therefore, the attached image is the Lewis structure of .
The answer is <span>non-biodegradable and subject to bioaccumulation and/or bioamplification.
DDT (dichlorodiphenyltrichloroethane) is persistent, non-degradable insecticide and organic pollutant readily accumulated to soils and consequently affects organisms.
DDE (</span><span>dichlorodiphenyldichloroethylene) is non-degradable pesticide toxic to birds at the first place.
PCBs (polychlorinated biphenyls) are non-degradable organic compounds very toxic to the environment.
PBDEs (polybrominated diphenyl ethers) are non-degradable compounds very toxic to environment, even able to affect brains of animals in the development period.</span>
Hmmmm i understand but i wanna know what to measure or whats about?
The two atoms shown in the equation are CALCIUM and oxygen.
<span>You start off with a neutral calcium atom with a shell of two electrons, a shell of 8 around that, a shell of 8 around that, and a shell containing 2...with no charge. </span>
<span>20 protons + 20 electrons. </span>
<span>You also have an oxygen atom with a shell of 2, and a shell of 6...with no charge. </span>
<span>8 protons + 8 electrons. </span>
<span>Each ionizes to form a calcium ion with 2 electrons removed (from the outer shell), leaving a +2 charge (20 protons, 18 electrons)... </span>
<span>and an oxygen ion with 2 electrons added (to the outer shell), leaving a -2 charge (8 protons, 10 electrons). </span>
<span>Their electrostatic attraction causes them to come together to form an ionic compound of CaO in a crystal lattice.</span>
