NEEEEEDD HELP!CHEMISTRY

Answer:

A substance that has a fixed chemical composition throughout is called a pure substance such as water, air, and nitrogen. A pure substance does not have to be of a single element or compound.

Explanation:

Compound: A substance that contains more than one element

pure substance: is made up of one substance made up of only one type of molecule

Answer:

O lowering the temperature of the system

Answer:

The answer is D.

Explanation:

Volume (V) = l x w x h

V = 4 x 5 x 1.2

V = 20 x 1.2

V = 24

Density = Mass/Volume  or D = M/V  

D = 85,000/24

D = 3541.66666666

Answer: smaller, larger

Explanation:

Cations are always {smaller} than the parent atom. Anions are always {larger} than the parent atom.

Cations are always smaller than the parent atom, and anions are always greater than the parent atom.

The term "parent atom" refers to an atom that has not yet undergone any chemical transformation. A parent atom is one that is discovered in its initial state.

Because they contain fewer electrons while maintaining the same nuclear charge, cations are always smaller than their parent atoms. Because the protons in the nucleus are holding the remaining electrons more tightly, their radii are less than those of the parent atoms. In the case of anion, this is the opposite.

Due to variations in electron-electron repulsion, the ionic radii of cations and anions are always less or bigger than the parent atom, respectively. The trends in ionic radius follow those in atomic size.

Thus, Cations are always smaller than the parent atom, and anions are always greater than the parent atom.

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Answer:

I don’t know what recording station you’re referring to but, When seismic waves reach the seismograph, a graphical record, or seismogram, is produced

Explanation:

The seismic waves hitting the recording station has been resulted in the seismograph, that has been evident of the earthquake.

The seismic wave has been the radiation, with the result of the movement of the earth surface. The movement has been result in the earthquake.

The intensity of the earthquake has been measured by seismograph on the Richter scale. The seismic wave results in the movement of the leads to the production of the seismograph.

The seismic waves hitting the recording station has been resulted in the seismograph, that has been evident of the earthquake.

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Answer : The correct option is, Magnesium because it is a group 2 element with two valence electrons.

Explanation :

Element = Calcium

Atomic number = 20

Electronic configuration of Ca =  

Number of valence electrons in Ca = 2

The number of inner shell electrons in Ca = 18

This option is wrong because lewis-dot structure shows only valence electrons not inner shell electrons.

Element = Carbon

Atomic number = 6

Electronic configuration of C =  

Number of valence electrons in C = 4

This option is wrong because only outermost p-sublevel electrons are not showing in lewis-dot structure.

Element = Lithium

Atomic number = 3

Electronic configuration of Li =  

Number of valence electrons in Li = 1

This option is wrong because it has only 1 electron in outermost shell.

Element = Magnesium

Atomic number = 12

Electronic configuration of Ma =  

Number of valence electrons in Ma = 3

This option is correct.

Lewis-dot structure : It is defined as the structure in which valence electrons of the atom is shown as dots.

ANOTHER EXPLANATION:

Answer: C. Magnesium, because it is a group 2 element with two valence electrons.

An atom's Lewis dot structure has two dots. Which of the following elements could it be, and why?

A. Calcium, because it is an alkaline earth metal with two inner shell electrons.

B. Carbon, because it has two electrons in its outermost p sublevel.

C. Lithium, because it is a group 1 element with two bonding electrons.

D. Magnesium, because it is a group 2 element with two valence electrons.

Explanation:

If you were to look at the periodic table magnesium would be in group 2. Since magnesium is in group 2 therefore it will have two valence electrons. Calcium is another possible answer because it is also in group two, but for this quiz it is incorrect. Lithium is incorrect because it is in group 1 and therefore it would only have 1 valence electron. Carbon is also incorrect because it is in group 14 so it would have 4 valence electrons. Hope this helps and makes sense.

Good Luck!!

Have a great day Studying!

The Lewis dot structure of an atom has three dots. With three valence electrons and belonging to group 13, which of the following elements may it be?

The semi-metal boron (B) and the metals aluminum (Al), gallium (Ga), indium (In), and thallium (In) are all members of the boron family (Tl). The periodic table's fifth element, boron (Z=5), is found in Group 13. It is categorized as a metalloid because of its characteristics, which combine those of metals and nonmetals.

The Periodic Table of Elements places these elements in Group 13 (XIII) of the p block. Metallic elements include thallium, gallium, indium, and aluminum. In their outermost shells, they each have three electrons shell with the valence electron configuration ns2np1 (one electron in the p orbital and a complete s orbital).

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.

Answer:

The shape of a molecule is mostly determined by repulsion among the pairs of electrons around a central atom.

Answer:

a

Explanation:

There are various kind of elements that are present in periodic table. Some elements are harmful, some are radioactive, some are noble gases. Therefore, the correct option is option A.

Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.

Periodic table help a scientist to know what are the different types of elements are present in periodic table so that they can discover the new elements that are not being discovered yet.

Along period, electronegativity increases. along group electronegativity decreases. The same trend is followed by  first ionization energy in periodic table.

Therefore, the correct option is option A.

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Based on their definitions, electron affinity could be considered the opposite of electron affinity. This is the force required to remove an electron from an atom while it is gaseous, or the propensity of an atom to lose electrons.

The electron is a subatomic particle with a negative one elementary charge electric charge. Due to their lack of components or substructure, electrons, which are part of the lepton particle family's first generation, are typically regarded to be elementary particles.

An electron is a negatively charged subatomic particle that can exist either free or bound to an atom (not bound). Along with protons and neutrons, electrons are one of the three primary types of particles that make up an atom. Together, protons, neutrons, and electrons make up the atom's nucleus.

This is the force required to remove an electron from an atom while it is gaseous, or the propensity of an atom to lose electrons. Conceptually, this is the polar opposite of electron affinity.

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The answer would be ionization energy

Answer:

Melting point is the temperature at which solid and liquid phases of a substance are in equilibrium.

Boiling point is the temperature at which its vapour pressure is equal to the external pressure.

Answer:

melting point is the temperature at which a solid changes into a liquid.  

boiling point, temperature at which the pressure exerted by the surroundings upon a liquid is equaled by the pressure

Explanation:

Answer:

0.25

Explanation:

no.of moles =10/40

Answer:

chromosome

Explanation:

Answer:

Most of the DNA in all animals, humans, and plants is found in the cell nucleus. Humans, animals and plants contains both DNA and RNA in the cell nucleus and they have to be present in all because every organisms structure and function directly depends upon them.

Explanation:

Answer:

the ability of a compound to dissolve

Explanation:

salt dissolves in water so it would be soluble.

oil does not dissolve in water so it is not soluble

Answer:

kdkekejdjejeneneenendjenejekeke do do do do do do d

Answer:

go ahead bro

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Answer: 57.C

Explanation: simple subtraction

Answer:

see this

Explanation:

Answer:

Lithium has 1 valence electron, Sulfur has 6

A is oxidized, B is reduced

A is reducing agent, B is oxidizing agent

Explanation:

when an atom loses electrons, it is oxidized

when an atom gains electrons, it is reduced (almost think of when you add a negative number to a positive number, the positive number gets smaller or is reduced)

Answer:

ok you got it you just need to add.

Explanation:

add 5 times and she what you get.

Answer:

3Mg+2FeCl3------------3MgCl2+ 3Fe

Answer:

Research Skills enable people to identify a problem, collect informational resources that can help address the problem, evaluate these resources for quality and relevance and come up with an effective solution to the problem.

Explanation:

It is important because it might increase you critical thinking skills and it's much more easy for you to collect data. It also helps you analyze information from different sources off the internet.

Answer:

a) Diamond can indeed be set on fire since it is made of carbon. ... Although diamond requires a higher temperature to burn, it does indeed burn via normal carbon combustion. You can even burn diamond in a regular flame if you are patient and conditions are right.

b) In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. The distinction between physical and chemical change is not clear cut.

c) Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons.

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Answer:

ACID RAIN

Explanation:

duh

hmmm water

Explanation:

Water can change if you put food coloring

in it

Answer:

To lose valence electrons.

Explanation: