Answer:
Explanation:
Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.
In 1897, J.J. Thomson discovered the electron by experimenting with a Crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged. In addition, he also studied positively charged particles in neon gas.
Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny and heavy nucleus. Rutherford designed an experiment to use the alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure.
The Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons. Bohr was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element.
The Sun is the major source of energy for organisms and the ecosystems of which they are a part. Producers, such as plants and algae, use energy from sunlight to make food energy by combining carbon dioxide and water to form organic matter. This process begins the flow of energy through almost all food webs.
Answer:
39 × 10²³
Explanation:
142.5/22 = 6.47 mole
Then n = n of molecules / nA = 39.01 × 10²³
<span>what volume of ammonia must you measure?
1.50 moles NH3 ( 22.4 L / 1 mole ) = 33.6 L NH3 should be measured
</span><span>how many molecules of nacl are in 23.40 grams nacl
23.40 g NaCl ( 1 mol / 58.44 g) (6.022 x 10^23 molecules / 1 mol ) = 2.4113 x 10^23 molecules
Hope these answer the questions. Have a nice day.</span>
The lone pair of electrons in Caffeine are shown in RED color in attached figure.
Details:
In chemistry there are two types of electrons.
i) Bonding Pair Electrons:
These are those electrons which are being shared and are involved in making bonds. They are also called as sharing electrons. In given structure all the solid bonds either single or double are made up of bonding pair electrons.
ii) Lone Pair / Non-Bonding Pair Electrons:
Those electrons which doesn't take part in bonding and are not shared between atoms. In given structure the lone pair of electrons are found only on nitrogen atoms (single lone pair) and oxygen atoms (two lone pair of electrons) respectively.