Los elementos que forman aniones con carga -1 y una capa externa estable de ocho electrones pertenecen al grupo de los: halógenos.
Para alcanzar la estabilidad, los átomos siguen la regla del octeto: ganan, pierden o comparten electrones para tener 8 electrones en su capa externa (capa de valencia).
Los elementos del Grupo 17 de la Tabla Periódica, conocidos como halógenos, tienen 7 electrones en su capa de valencia. Así, tienden a ganar 1 electrón para completar su octeto. Como los electrones tienen carga negativa, al ganar 1 electrón los aniones quedan con una carga de -1.
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A researcher wants to conduct an experiment to see how the amount of breakfast a student eats
affects their performance in school. He makes 2 groups, one group consumes 300 calories in
the morning while the second group does not eat breakfast at all. After 2 weeks he compares
the students test scores and every student takes the same tests. Identify the following:
a. Control Group:
b. Independent Variable:
c. Dependent Variable:
The control group are the students who eat no breakfast. The independent variable is the consumption of breakfast. The dependent variable is the performance of students in school.
In an experiment, the control group is the group that did not receive the treatment. The treatment in this case is the consumption of breakfast. Hence the group that did not consume breakfast is the control group.
The independent variable is the variable that is being manipulated and its effect evaluated. The manipulated variable here is consumption of food.
The dependent variable is the variable that is being measured. In this case, it is the performance of students at school.
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Freezing water cracking limestone
a
Chemical Change
b
Physical Change
Answer:
Freezing water and cracking limestone are physical changes.
Can lead ii carbonate conduct electricity? Explain your answer
Solid Lead II carbonate can not conduct electricity because it is insoluble in water.
First of all, we must establish the fact that ionic solids conduct electricity in solution because they can be broken up into ions in solution.
In the solid state, they do not conduct electricity because the ions are strongly bound by electrostatic forces.
However, if an ionic substance is insoluble in water, its ions are not available to conduct electricity since ions are the charge carrier in solution. As a result of this, such a substance will not conduct electricity.
Since Lead II carbonate is insoluble in water, its ions are not available hence the substance does not conduct electricity.
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How to convert 2.37 l tp dl?
Answer:
23.7
Explanation:
The formula to convert from L to dL is:
dL = L x 10
In a nuclear reaction 5.02 ×10^-28 kg of a radioactive sample reduced to 4.02×10^-29 Kg producing 259.74 Mer energy. Calculate the speed emitted. [ mer= 1.6×10^-13].
I need urgent answer with method pls
Answer:
2jd
Explanation:
Heueneirnfjgnjfbgjgfj,fqiywyjeukdhsjdshmsjhskdlhkddvndkurmbsjhsmjdjgsjlsmhudksyke
How can you determine the number of shells in an atom of a certain element, based
on the element's position on the periodic table?
Answer: At some point in your chemistry education, you may have been introduced to the song “The Elements in which Tom Lehrer does a rapid
fire musical rendition of all the elements' names. Like me, you may even have been offered the opportunity to memorize this song for extra credit. If so, it’s possible that you still remember the names of all the elements, which is an impressive feat—not to mention a fun trick to pull out at parties.
Explanation:
How could you describe the changes that happen when carbon changes form from graphite to diamond?
The change from graphite to diamond is a chemical change.
A chemical change involves the rearrangement of atoms in a substance. In other words, the "composition" of the substance changes when a chemical change takes place.
This is clearly seen when graphite changes to diamond. The arrangement of carbon atoms changes as reflected by the change in the density of graphite when it is converted to diamond.
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(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
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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Help Please I need to finish TODAY
Answer:
A. > digestive and circulation
B. > digestive and excertory
C. > nervous and muscluar
D.> digestive and circulation
hope this helps !! please make brainlest!
What is required for electrons to move from the stable energy level to an excited state?
answer
When an electron temporarily occupies an energy state greater than its ground state, it is in an excited state. An electron can become excited if it is given extra energy, such as if it absorbs a photon, or packet of light, or collides with a nearby atom or particle
he difference between a stable isotope and an unstable isotope of an element is that __________. ANSWER the unstable isotope decays and is always transformed into a stable form of the same element the stable isotope has a nucleus that decays spontaneously and is radioactive the unstable isotope has a nucleus that does not decay spontaneously and is never radioactive the stable isotope has a nucleus that decays spontaneously but is not radioactive the unstable isotope has a nucleus that decays spontaneously, is radioactive, and can be transformed into an atom of another elemen
We know that any known element is defined by the number of protons in its nucleus (which is the same as the number of orbiting electrons).
We can define isotopes as the atoms of the same element but that have a different number of neutrons in the nucleus. The correct statement of the difference between stable isotopes and unstable isotopes is:
"The difference between a stable isotope and an unstable isotope of an element is that the unstable isotope has a nucleus that decays spontaneously, is radioactive, and can be transformed into an atom of another element"
Particularly we can define two of these, the stable isotopes, that can remain as they are for a lot of time, and the unstable isotopes, that have more neutrons in its nucleus than a stable isotope, and because having those extra neutrons in the nucleus needs energy, eventually the isotope will experience a spontaneous radioactive decay, which "breaks" the nucleus in different ways, and, in some cases, generates different elements in the process.
Then we can conclude that:
"The difference between a stable isotope and an unstable isotope of an element is that the unstable isotope has a nucleus that decays spontaneously, is radioactive, and can be transformed into an atom of another element"
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Which of the following
statements is true about the
charges of protons and neutrons?
A. Protons and neutrons have the same charge.
B. Protons have a positive charge and neutrons
have no charge.
C. Protons have a negative charge and neutrons
have a positive charge.
Answer:
B
Explanation:
Protons have a positive charge while neutrons have no charge because they are neutral.
Answer:
b
Explanation:
b/ce protons have+ charge while neutrons have no charge
Which of the following is an example of climate?
The polar regions have long winters and short, cool summers.
Humidity levels are high today.
Canada experienced an unusually warm summer this year.
Tornados formed across Oklahoma yesterday.
Answer:
"The polar regions have long winters and short, cool summers."
Explanation:
Climate is the average of that weather. The climate record also includes extreme values such as record high temperatures or record amounts of rainfall.
For Climate example:
You can expect snow in the Northeast in January or for it to be hot and humid in the Southeast in July.
When a gas is dissolved in a liquid, what happens when the pressure increases?
Answer: B, the gas is being squeezed out of the liquid.
Explanation: The gas does not want to be trapped inside of the liquid, so it is trying to force it’s way out. Therefore creating more pressure in the container or whatever the liquid is being held in.
Answer: more gas dissolves into the liquid
Explanation: just got it wrong thats the right answer
Why will goats protect wildfires
Explanation:
The goats can stretch their necks up to 7 feet, biting branches and low lying leaves. They eat poison oak and can clear rocky cliffs -- something other livestock can't do. And it's easier to control where the goats cut a fire break, unlike controlled burns -- another method of removing wildfire fuel.
pls mark me branilestWhen measuring the volume of an object you are finding the?
A. Single dimension of an object
B. Amount of 2 dimensional space an object covers
C. Amount of 3 dimensional space the object occupies
D. Amount of 4 dimensional space an object occupies
Answer:
C. Amount of 3 dimensional space the object occupies
Explanation:
Single dimension is a laminar
Amount of 2 dimension is area
Amount of 4 dimension is negligible
[tex].[/tex]
Answer C. Amount of 3 dimensional space the object occupies
Explanation:
Single dimension is a laminarAmount of 2 dimension is areaAmount of 4 dimension is negligible
What is density? How do you find it?
Density is the measure of a mass per unit volume of a material substance
density= Mass/volume
The unit of density is g/cm^3
What accurately describes the reactants of a reaction
Answer:
Substance that are used in the reaction
Explanation:
I hope this will help you
Answer:
Substances that are used in the reaction. Hope my answer helps you!
In comparing groups, the first or the second, which group was more precise or was the precision the same
Comparing the data obtained online, the first group is more precise
The reason the above selection is correct is as follows;
Question: Parts of the question appear missing from a similar question online and included here;
First Group:
[tex]\begin{array}{|c|c|c|c|c|c|c|} Team \ a &Team \ b&Team \ c&Team \ d&Team \ e&Team \ f&Team \ g\\2.77 \ cm&2.60 \ cm&2.80 \ cm&2.65 \ cm&2.75 \ cm&2.65 \ cm& 2.68 \ cm\end{array}\right][/tex]
Second Group
[tex]\begin{array}{|c|c|c|c|c|c|c|} Team \ a &Team \ b&Team \ c&Team \ d&Team \ e&Team \ f&Team \ g\\2.70 \ cm&2.78 \ cm&2.62 \ cm&2.65 \ cm&2.75 \ cm&2.80 \ cm& 2.60 \ cm\end{array}\right][/tex]
Calculations for the first group:
The average = (2.77 + 2.60 + 2.80 + 2.65 + 2.75 + 2.65 + 2.68)/7 = 2.7
The range = 2.80 - 2.60 = 0.20
The approximate ± range of the average = ±0.2/2 = ±0.1
The precision of the first measurement is 2.7 ± 0.1 cm
Calculations for the second group:
The average = (2.70 + 2.78 + 2.62 + 2.65 + 2.75 + 2.80 + 2.60)/7 = 2.7
The range = 2.80 - 2.60 = 0.20
The approximate ± range from the average = ±0.2/2 = ±0.1
The range of values from the average is approximately ±0.1 cm
The precision of the first measurement is 2.7 ± 0.1 cm
Method to determine precision:
Precision is given by the finding the average deviation and the standard deviation as follows;
[tex]\mathbf{Average \ deviation} = \dfrac{\sum \left | x - \mu \right |}{n}[/tex]
[tex]\mathbf{Standard\ deviation} =\sqrt{\dfrac{\sum \left ( x - \mu \right )^2}{n}}[/tex]
Where;
μ = The mean or average = 2.7
n = The number of items (count) of the data = 7
For the first group, we have;
[tex]\mathbf{\dfrac{\sum \left | x - \mu \right |}{n}} = \dfrac{0.07 + 0.1 + 0.1 + 0.05 + 0.05 + 0.05 + 0.02 }{7} = \mathbf{0.062857}[/tex]
The average deviation of the first group = 0.062857
∑(x - μ)² ≈ 0.0328
[tex]\mathbf{The \ standard\ deviation} =\sqrt{\dfrac{0.0328}{7}} \approx \mathbf{0.068452}[/tex]
For the second group, we have;
[tex]\mathbf{\dfrac{\sum \left | x - \mu \right |}{n}} = \dfrac{0.0+ 0.08 + 0.08 + 0.05 + 0.05 + 0.1 + 0.1 }{7} = \mathbf{0.06571428571}[/tex]
∑(x - μ)² ≈ 0.0378
[tex]\mathbf{The \ standard\ deviation} =\sqrt{\dfrac{0.0378}{7}} \approx \mathbf{0.073485}[/tex]
By using the average deviation, and standard deviation values, the deviation of the second group is more than the first group and therefore the first group is more precise
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How would you prove that Sodium hydroxide is a
Base without using litmus paper
to test ? Give the equation for the
reaction
place the letters on the spectrum below from least scientific two more scientific A. All living things are composed of one or more cells. We know this because every living thing examined to date has
been found to be composed of one or more cells.
B. If you break a mirror, you will have seven years of bad luck.
C. The Earth is flat. Anybody can see that!
D. Taking Vitamin C prevents the common cold. Linus Pauling, the Nobel laureate who discovered the structure of
Vitamin C, says it does.
E. Humans have a soul. I believe this because it says so in the Bible. The soul is what separates us from animals.
F. The rate of acceleration of all falling objects on Earth is constant. Two spheres of identical diameter and volume are
dropped from the top of a building; one is made of steel, the other made of a plastic polymer. They both will accel-
crate at the same rate (32 ft/s) and hit the ground at the same time.
Answer: B, C, E, D, A, F
Explanation: It is a little difficult to assign a regid order to these statements. Much depends on one's definition of "more scientific." My thoughts:
B: Only in the movies
C: Flat Earthers still exist, but no one has ever fallen off the edge, that I'm aware of
E: I've had a few pets with souls. My cat has it in for me.
D: I met Linus Pauling twice - he was too enthusiastic with his vitamin C and did not critically evaluate the evidence, but he was far more correct than the Flat-Earthers.
A: Lots of good evidence, although it can also depend on the definition of "living," Is a virus "living?"
F: Yep, I've done it myself. Heavier object have more inertia - they are the couch potatoes of physics. They will take their own time to get moving.
what are the three formula of mole?
[tex] \huge \boxed{\mathfrak{Formulas} \downarrow}[/tex]
For all[tex] \large \sf \: mole = \frac{mass}{molar \: mass} \\ [/tex]
For gases[tex]\large \sf \:mole = \frac{volume}{molar \: volume} \\ [/tex]
For solutions[tex]\large \sf \:concentration \: ( \frac{g}{ {dm}^{3} } ) \\\large \sf \: = \frac{mass(g)}{volume( {dm}^{3} )} [/tex]
You can substitute mass with mole for concentration (mol/dm³).WHATS THE FREEZING POINT FOR WATER
Answer:
0 degrees Celcius and 32 degrees fahrenheit
Explanation:
Which of the following statements correctly explains why the excretory system is different from the digestive system? (1 point)
The excretory system is different from the digestive system because it removes waste from the body by filtering water, which
includes mostly the by-products of metabolism.
The excretory system is different from the digestive system because it removes waste from the body by filtering urine, which
includes mostly the by-products of metabolism
The excretory system is different from the digestive system because it removes waste from the body by filtering food, which
includes mostly the by-products of metabolism. filtering food
SS
2
The excretory system is different from the digestive system because it removes waste from the body by filtering blood, which
o
includes mostly the by-products of metabolism
U.
Hey
Answer:
The excretory system removes waste from the body. remove waste from the blood. The digestive system breaks down the food you eat into nutrients that provide energy and building materials for cells. The digestive and excretory sytems work together to process the food that you eat.
What is the relationship between a calorie and a
joule?
SURELY SOMEONE HELP it’s urgent plllss I’ll brainlist u/5 star!!! answer the ones u know. :)
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
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1. Why Isn't Hess's law helpful for calculating the heat of reaction Involved in the conversion of diamond to graphite?
Answer:
This law is not applicable or not helpful in the conversion of diamond to graphite because both are just allotropes of carbon along with C60 (Buckminsterfullerene or buckyball), C540, C70, amorphous carbon, and carbon nanotube
Explanation: did that help? hope it did!
on what factors the Modern Periodic Table is different from that of the Mendeleev's periodic table?Write any two reasons.
Explanation:
The main difference between Mendeleev and Modern period table is that Mendeleev's periodic table orders the elements based on their atomic mass whereas Modern periodic table orders the elements based on their atomic number.
Mendeleev's periodic law states that the physical and chemical properties of the elements are a periodic function of their atomic weights while Modern periodic law states that physical and chemical properties of elements are a periodic function of their numbers.
Which of the following best describes a scientific model?
Question 6 options:
Something used to represent an idea or process
A way to prove a theory is true
A direct experience in nature
A prediction that can be tested
Explanation:
idea= hypothesis
xperience in nature= read Darwin's theory..
with birds from Galapagos island or rain forest environment., had proven that the shape of a bird's beaks, determined what their diet consisted of In the wild.
captured birds from such countries, has proven, an omnivore or seed eater...through testing plus dissection.
If a sample of water has a mass of 200g and the final solution has a mass of 230g, how much solute dissolved in the water?