Nguyên tố hoá học là gì

Answers

Answer 1

Nguyên tố hóa học, thường được gọi đơn giản là nguyên tố, là một chất hóa học tinh khiết, bao gồm một kiểu nguyên tử, được phân biệt bởi số hiệu nguyên tử, là số lượng proton có trong mỗi hạt nhân.

Hope U like my answer and my answer helped U......
Nguyn T Ho Hc L G

Related Questions

Which of these answers describes a scientific law?
(Pls)

Answers

Answer:

big ablsolty long pp

Explanation:

dong

SURELY SOMEONE HELP it’s urgent plllss I’ll brainlist u/5 star!!! answer the ones u know. :)

Answers

Answer:

3 exothermic reaction. only that much

Hi,

These are the answers.

• Question 2. C , Substance dissolves

• Question 3. D , Exothermic reaction

• Question 4. C , Endothermic reaction takes place

• Question 5. A , the products formed has more energy than reactants

Hope it helps you... pls mark brainliest if it helped you

Which of the following are decomposition reactions?
A. CH4 (9) +202 (9) - CO2 (g) + 2H20 (9)
B. N2 (9) + 3H2 (9) ► 2NH3 (9)
C. CaCO3 (s) - Cao (s) + CO2 (9)
D. 2H20 (1) ► 2H2 (9) + O2 (9)

Answers

Answer:

C and D

Explanation:

A reaction is said to be decomposed, if the reactant is broken down to liberate single element.

Which element would most likely lose electrons to form positive ions when bonding with other elements?

rubidium (Rb)

gallium (Ga)

argon (Ar)

iodine (I)

Answers

The correct answer to the question is Rubidium (Rb)

Rubidium (Rb) is a group 1 element and as such, it can form bond by losing it's valence electron (i.e 1 electron) easily.

Gallium (Ga) is a group 13 element. It can only form bond by losing it's 3 valence electrons.

Argon is a group 18 element. This group has completely filled outermost shell and are very stable. They do not involve in bond formation.

Iodine (I) is a group 17 element. It is more difficult for this group to lose its 7 valence electrons hence, they form bond by accepting 1 electron.

With the above information, we can conclude that Rubidium will most likely lose electron to form bond.

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Answer:

(Question 1)Which element would most likely lose electrons to form positive ions when bonding with other elements?

(Answer) rubidium (Rb)

(Question 2) Which statement about sodium chloride is correct?

(Answer) The sodium atom transfers electrons to the chlorine atoms to form ionic bonds.

(Question 3) Based on their locations in the periodic table, which two elements are most likely to form covalent bonds with each other?

(Answer) nitrogen (N) and oxygen (O)

(Question 4) Which phrase best describes electronegativity?

(Answer) the relative strength with which an element attracts electrons in a chemical bond

(Question 5) Based on the information in the table, which pair of elements would likely form the least polar bonds with each other?

(Answer) bromine and nitrogen

Explanation:

just finished the quick check enjoy UwU

Vapor pressure of any liquid _______. A. increases with increases in temperature B. increases with decreases in temperature C. is not affected by changes in temperature D. increases with increases in volume of the liquid E. None of the Above

Answers

Answer:

increase with increases in temperature

Explanation:

please mark me brainleast

What are the answers to these?

Answers

Answer:

1)physical change

Explanation:

2)chemical change

underline and identify the parts of the text on this page that use examples of how the flow of the matter through a system is driven by energy and can do the work.​

Answers

The parts of the text on the page that use examples of how the flow of matter through a system is energy driven and has the capacity to do work are;

1) The flow of water down rivers passing through hydro power dams to perform the following works;

River bank particle erosionElectric power generation

2) The flow of electrons that corresponds to the flow of electricity (in the reverse direction) to perform the following works;

Light bulbs turn onTelevisions are powered

3) The lifting of the hammer by the cam which gains gravitational potential energy that is converted to kinetic energy as the hammer drops

The hammer is repeatedly lifted and dropped by the cam to do the following work

Hammering a metal piece into shape

4) The chemical potential energy stored in bonds by virtue of the relative atomic distances which produces kinetic energy from the chemical potential energy

Lear more about energy conversion here:

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A pan containing 20.0 grams of water was allowed to cool from a temperature of 95.0 °C. If the amount of heat released is 1,200 joules, what is the approximate final temperature of the water?
75 °C
78 °C
81 °C
87 °C

Answers

Answer:

81 °C

Explanation:

This is a calorimetry question so a few things you will need for this. The calorimetry equation q=mcΔT & the specific heat of water (4.2J/g•°C). Other definitions are:

q = heat added/released by a sample

m = mass of sample

c=specific heat of sample

ΔT = change in temperature

from here we can rearrange the equation to state:

q/(mc) = ΔT

1200J/((20.0g)(4.2J/g•°C)) = ΔT

14°C = ΔT

If the starting temperature was 95.0°C and we know that the temperature was cooled by 14°C then the final temperature of the water would be 81.

Answer:

C. 81 c

Explanation:

took the test :)

Can someone plz help me? Plzz giving brainliest!

(Plz chose 3 questions)

Answers

Answer:

Facts: A D and maybe C I think you are intended to say C

Explanation:

A is certainly not an opinion. It is either true, or it is not. I think it is intended as a fact.

B is an opinion (which I think is true)

C is kind of iffy. It might be true and it might be an opinion. In looking it up, it is factually incorrect. Cats are related to wildcats in the middle east.

D is also iffy. They can just eat disease free rodents. I'd classify it as more opinion than fact.

E. definitely an opinion.

Come up with 2 examples of derived units from everyday life.

Answers

Answer:

answer

Explanation:

Area : Square Meters,

Volume : Cubic Meters,

Density : Kilograms per Meter Cube,

Velocity : Meters per Second Squared,

Force : Newtons (Mass multiplied by Acceleration or Mass multiplied by Displacement divided by Time squared)…..

What is the approximate mass of one electron?

Answers

Answer:

9.1093837015 × 10^−31 kg

Very small mass

Freezing water cracking limestone

a
Chemical Change
b
Physical Change

Answers

Answer:

Freezing water and cracking limestone are physical changes.

(Physical Science)

Which group of metals includes elements with one valence electron? (1 point)

A. alkaline earth metals
B. rare earth metals
C. alkali metals
D. transition metals​

Answers

Answer:

C

Explanation:

alkali metals are the Group I elements, which have 1 electron in their valence shells

Answer:

Alkali metals are the elements which have only one valence electron in their outermost or ultimate shell.

Explanation:

Alkaline Earth metals have 2 valence electron in their outermost shell and readily give up their 2 electron to achieve stability.

Rare Earth Metals have 3 valence electron in their outermost shell and they have high magnetic moments and divert range of magnetic structure.

Alkali Earth metals have 1 valence electron.

Transition metals generally have 2 valence electron .

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Plzzzzzz help me Write electronic configuratof sodium and chlorine in the term of subshell ?

Answers

Answer:

ans:Ne=2,8,1

ans:2,8,7

what is the concentration of hydrogen ion, H+, present in a water sample if 100. ml of the sample requires 7.2 ml of 2.5 x 10 -3 M NaOH to be neutralized

Answers

Answer:  1.8x10^-4 M H+

Explanation:  The number of moles of NaOH added to the 100 ml soultion will be equal to the number of moles of H+ present in that solution.  

Moles NaOH in 7.2 ml of 2.5x10^-3 M NaOH

(2.5x10^-3 M NaOH) is the same as 2.5x10^-3 moles NaOH/liter

(2.5x10^-3 moles NaOH/liter)*(7.2 ml)*(1 liter/1000ml) = 1.8x10^-4 moles NaOH used to titrate 100 ml of the acid.  That means there was 1.8x10^-4 moles of H^+ in 100 ml.  

Concentration of H^+ = (1.8x10^-4 moles H)/0.100 l) = 1.8x10^-4 M H+

(pH of 3.74)

A sample of brass weighing 1.203g was analyzed. The zinc in the alloy was reacted with 35.123g of HCl in excess, according to the balanced equation:
Zn (s) + 2HCl(aq) - > H2(g) + ZnCl2 (aq)
After all the zinc reacted, the mass of the remaining solution weighed 36.309g

What was the mass of H2 produced?
What mass of Zn reacted?
What was the percentage of Zn (by mass) in the alloy?

Answers

The number of moles of reactants and products can be used to obtain the mass of products formed. The results obtained are as follows;

The mass of hydrogen produced is 0.0174 gramsThe mass of zinc produced is  0.5688 gramsThe percentage by mass of zinc in the brass alloy is 47.3 %

The question says that HCl was in excess. It means that after the reaction, we will have unreacted HCl(aq) and  ZnCl2(aq) in the remaining solution.

Hence;

Mass of ZnCl2(aq) formed = 36.309g - 35.123g  = 1.186g

Number of moles ZnCl2(aq) formed = [tex]\frac{mass of ZnCl2(aq) formed}{molar mass of ZnCl2}[/tex]

[tex]\frac{1.186g}{136.286 g/mol}[/tex] = 0.0087 moles

From the reaction equation;

[tex]Zn (s) + 2HCl(aq) - > H2(g) + ZnCl2 (aq)[/tex]

To obtain the amount of Zn reacted

1 mole of Zn yields 1 mole of ZnCl2

x moles of Zn yields 0.0087 moles of ZnCl2

x = 0.0087 moles of Zn

a) 1 mole of Zn yields 1 mole of H2

0.0087 moles of Zn yields 0.0087 moles of H2

Mass of H2 = 0.0087 moles of H2 * 2 g/mol = 0.0174 grams

b)

Mass of Zn reacted =  0.0087 moles of Zn * 65.38 grams/mole = 0.5688 grams

c)

Percentage of Zn in the alloy = 0.5688 grams/1.203g * 100 = 47.3 %

https://brainly.com/question/14595258

Chemical changes can change which properties of a substance?
Group of answer choices

Reactivity

Color

Malleability

All of the above

Answers

Answer:

» Reactivity and color

Explanation:

though color is very minor answer because it also relates to a physical property.

[tex].[/tex]

what happens to the food dye in hot water?

Answers

Answer:

The food coloring mixes through the hot water faster than it mixes with the cold water. The reason for this is because  in hot water, the water molecules have more energy and are moving faster than the molecules of cold water. This makes it way more easier for the dye to get mixed throughout the hot water.

Explanation:

what is sublimation ​

Answers

Explanation:

Sublimation is the conversion of a substance from the solid to the gaseous state without its becoming liquid. ... Freeze-drying of food to preserve it involves sublimation of water from the food in a frozen state under high vacuum. See also vaporization; phase diagram.

What effect does fermented sugar have in beer brewing

Answers

Answer:

If the sugar concentration level of the must becomes too high at any given point--either at the beginning or during the fermentation--it starts to have an inhibiting effect on the yeast's ability to produce alcohol. In other words, the higher sugar concentration starts to act as a preservative effecting the fermentation in a negative way.

Explanation:

Fermentation is the process by which yeast converts the glucose in the wort to ethyl alcohol and carbon dioxide gas -- giving the beer both its alcohol content and its carbonation.


May someone help me with the answer to this question I’ve been stuck on it

Answers

Explanation:

No, that would be incorrect

Answer:

There arre two main parts of the atom, the nucleus and the orbital rings. The three subatomic particles are contained in each of these, the proton and neutron together in the nucleus and the electrons orbiting in the rings.

Give an example of a non-biological chemical reaction that involves carbon. Name the process that converts a solid compound into a gas.

Answers

Answer:  The combustion of methane (CH4) with O2.

Explanation:  This is a chemical reaction involving carbon:

 CH4 + 2O2 = CO2 + 2H2O

Solid solid soluton example​

Answers

Explanation:

rice and rice coatssalt and sugarsand and mudwheat flour and corn flour

If you burn a citronella candle near your picnic will it keep mosquitoes away

Answers

Answer:

Thanks!!!

Explanation:

Answer:

true

Explanation:

HELP! Fill in the blanks:
The net charge of an atom is equal to the difference between the_____
in the atom's nucleus and the_____

Answers

Answer:

I don't know

Explanation:

is today your test

1. If an atom has an equal number of protons and electrons, its net charge is 0. If it gains an extra electron, it becomes negatively charged and is known as an anion. If it loses an electron, it becomes positively charged and is known as a cation.

2. The nucleus of an atom is the atom's dense and heavy core with a positive charge




I’m not so sure about the second one but I hope I helped :)

Compare and contrast the three types of mixtures (solutions, colloids, and suspensions).

Answers

Answer:

solutions is a homogenous mixture while colloids and suspensions are heterogeneous mixtures made up of 3 or more substances

Explanation:

homogeneous- made up of one thing

heterogeneous- made up of 2 or more things

surely help:) I’ll brainlist!

Answers

Answer:

A. The product formed have more energy than the reactants.

This is because it is an endothermic reaction.

[tex].[/tex]

WILL MARK BRAINLEST IF CORRECT!
1) Burning toast physical or chemical
2) Cooking eggs: physical or chemical
3) Melting butter: physical or chemical
4) Removing the pulp (solid) from the orange juice using a juice strainer.: physical or chemical
5) Cutting the toast with a knife: physical or chemical
6) Digesting the food: physical or chemical

Answers

Boi what the hell boi
1) Chemical
2) Chemical
3) Chemical
4) Physical
5) Physical
6) Chemical

Which of these are PHYSICAL changes?
А.
cutting, tearing, freezing, thawing, folding.
mixing without chemical changes
B.
burning, rusting, forming a new substance from
two different substances, exploding, cooking

Answers

Answer:

the answer to this problem is a

Please help me with this chemistry

Answers

Answer:

D=1.56g/mL

Explanation:

Density=m/v

D=14.06g/(24mL-15mL)

D=14.06g/9mL

D=1.56g/mL

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