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3 years ago

The Greeks were the first to use the term _____. atom electron neutron proton

2 answers:

6 0

I think the correct answer from the choices listed above is the first option. The Greeks were the first to use the term atom. In 450 BCE, Democritus coined the term átomos which means "uncuttable" or "the smallest indivisible particle of matter".

kotegsom [21]3 years ago

3 0

Answer:

Atom

Explanation:

The Greeks first used the word "atomos" or atom.

There was a philosopher by the name of Leucippus of Miletus, and he had the idea that if you cut an object in half, and then in half again, and in half again, and so on... eventually you would get to a particle that cannot be cut in half (they were talking about the atom, however we now know that splitting an atom releases large amounts of radiation). The word atomos in Greek means "uncuttable".

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Discuss the significance of assigning an atomic mass of exactly 12 amu to the carbon-12 isotope.

evablogger [386]

Answer:

Cabon-12 has same average atomic weight and mass number.

Explanation:

carbon-12 has average atomic weight 12 amu and mass number of 12.

amu represents average of mass of a nucleon.

As carbon-12 has same average atomic mass and mass number therefore carbon-12 is a good standard to determine average mass of a nucleon.

Again, abundance of carbon-12 isotope is almost equal to 99%. Therefore fluctuation of average atomic weight from 12 amu is very very low.

So, carbon-12 is taken as a standard to determine mass of a nucleon.

Hence atomic mass of carbon-12 is 12 amu.

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3 years ago

Which metal is more active than H2?<br> (1) Ag (3) Cu<br> (2) Au (4) Pb

astraxan [27]

Answer is (4) - Pb.

According to the reactivity series of elements

- the elements which are above the hydrogen are more reactive than hydrogen.

- the elements which are below the hydrogen are less reactive than hydrogen.

Among the given choices, only Pb is placed above the hydrogen in the reactivity series and rest are below the hydrogen.

Hence, Pb is more active than hydrogen.

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3 years ago

What do all four animals have in common? cat worm spider crab

Free_Kalibri [48]

<span>They are composed of cells</span>

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2 years ago

The expected o-c-h angle in this molecule is degrees. the expected hybridization at the central carbon is

WINSTONCH [101]

Each neutral carbon atom contains four valence electrons and may form up to four electron domains. Possible hybridizations include

$sp^{3}$ , four electron domains, as in ethane $\text{C}_2\text{H}_6$
$sp^{2}$ , three electron domains, as in ethene $\text{C}_2\text{H}_4$
$sp$ , two electron domains, as in ethyne $\text{C}_2\text{H}_2$

Molecules of each of the three hybridization demonstrate spatial configurations that would maximizes the separation between the electron domains.

Carbon atoms with a $sp^{3}$ hybridization would demonstrate a tetrahedral configuration with a bond angle of approximately $109.5\textdegree{}$
Carbon atoms with a $sp^{2}$ hybridization would demonstrate a triangular planar configuration with a bond angle of $120\textdegree{}$
Carbon atoms with a $sp$ hybridization would demonstrate a linear configuration with a bond angle of $180\textdegree{}$

Bond angles are characteristic of the spatial configuration of electron domains and identifies the hybridization of the central carbon atom.

Note that each hydrogen atom contains only one valence electron and would form only single bonds. It takes two valence electrons for oxygen atoms to achieve an octet such that each oxygen form only two bonds at a single time. Therefore given the fact that the carbon is bonded to both hydrogen and oxygen, only the following hybridizations are possible

$sp^{3}$ in which the oxygen atom forms a carbon-oxygen double bond with the central carbon atom;
$sp^{2}$ in which the oxygen atom forms a single bond with the central carbon atom and with a second atom.

3 0

3 years ago

Saturn is about 1 429 000 km from the sun. how many meters is saturn from the sun?

stira [4]

Answer:

1.493 trillion

Explanation:

8 0

3 years ago

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