Which elements have two valence electrons?
A. Carbon
B. Magnesium
C. Fluorine
D. Sodium
Answer:
Magnesium
Explanation:
Magnesium is in group 2 of the periodic table. The group in which an element is found in tells us the number of valence eletrons it has.
HOPE THIS HELPED
Among the given elements, the element that have two valence electrons is Magnesium. The correct answer is option B.
Valence electrons are the electrons that are present in the outermost shell of an atom that are involved in chemical bonding. The number of valence electrons an atom has is determined by the group number it belongs to on the periodic table.
Magnesium belongs to group 2A on the periodic table, which means it has two valence electrons.
Carbon belongs to group 4A and has four valence electrons, while Fluorine belongs to group 7A and has seven valence electrons. And Sodium belongs to group 1A and has one valence electron.
Therefore, option B. Magnesium is the elements that have two valence electrons.
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What is the definition of hydro energy
Answer:
a form of energy that harnesses the power of water in motion—such as water flowing over a waterfall—to generate electricity.
Explanation
How is a carbon atom different from a hydrogen atom?
Answer:
Carbon atom is a chemical element with the symbol C and atomic number 6 ( electrons). While Hydrogen atom is an atom of the chemical element hydrogen that have only 1 electron.
Explanation:
The carbon atom different from a hydrogen atom, because the atomic number of hydrogen is 1 . The atomic mass number of hydrogen is also one. For the carbon atom, the atomic number is 6, and the atomic mass number of carbon is 12.
What is an atomic number ?The term atomic number is defined as the number of a chemical element in the periodic system. The elements are arranged in order of increasing number of protons in the nucleus.
The atomic number is situated at the upper left, or number of protons. In the middle is the letter symbol for the element. Atomic number is equal to the proton number or the number of protons found in the nucleus of every atom of that element.
Thus, Carbon atom is a chemical element with the symbol C and atomic number 6. Whereas hydrogen atom is an atom of the chemical element hydrogen that have only 1 electron and its symbol is H.
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the question is on the screenshot worth 20 points pls help
Answer:
Cell Y Only
Explanation:
Which of the following correctly lists the levels of organization from most complex to least complex? *
Community, Organism, Population, Ecosystem
Ecosystem, Community, Population, Organism
Population, Community, Ecosystem, Organism
Organism, Population, Community, Ecosystem
Answer:
The last option.
Explanation:
You can immediately eliminate the other options as an organism is clearly the least complex. Only one option begins w/ 'organism'.
Answer:
Its def A, if this helped subscribe to amiredagoat Yt
Explanation:
PLEASE HELPPP!!!!!! ASAP!!!!
Which of the following best describes cations? Question 19 options: A) They're negatively charged because they lost an electron. B) They're positively charged because they gained an electron. C) They're positively charged because the number of electrons remained the same. D) They're positively charged because they lost an electron.
Answer:D
Explanation:trust me bro
Answer:
D
Explanation: I took the test
What kind of fossil is made when a creature is buried under sediment and as that sediment forms into rock the hard materials like bones of the organism are formed into the rock?
Answer:
Mold fossil
Explanation:
It's called a mold fossil because they are formed when sediments bury an organism and then the sediments are changed into rock; then the organism decays thereby leaving a cavity in the shape of the organism
Molecules have Question 10 options: A) both potential and kinetic energy. B) neither kinetic nor potential energy. C) only potential energy. D) only kinetic energy.
Answer:
B?
Explanation:
Compare and contrast The two methods of making alcohol
Answer:
The table compares making ethanol by hydration of ethene (ethene and steam) to making ethanol by fermentation (sugar from plant material).
14. A researcher Is curious to find out what effect classical music has on people's level of relaxation
(as measured by heart rate). She suspects that listening to classical music will make people feel
more calm and relaxed. The researcher lets one group listen to classical music for one hour and
then do a relaxing activity, like reading or drawing for another hour. She lets the other group sit in a
qulet room for two hours (they hear no music). After two hours, she monitors the heart rate of each
participant to measure their level of relaxation.
What is the error in thls experiment design?
A. There are two independent variables: classical music and an additional relaxing activity
B. There are two independent variables: the amount of time and heart rates
C. There are two dependent variables: classical music and an additional relaxing activity
D. There are two dependent variables: the amount of time and heart rates
Answer:
It should be "B"
Explanation:
:) :) :) :) :) :)
If the temperature of a gas increased from 100 K to 200 K and the volume of a gas decreased from 20 L to 10 L, what is the new pressure if the original pressure was kPa?
Answer:
320pka
Explanation:
This is a complete question;
If the temperature of a gas increased from 100 K to 200 K and the volume of a gas decreased from 20 L to 10 L, what is the new pressure if the original pressure was 80kPa?
EXPLANATION;
Gas laws can be regarded as aws which relate the pressure, volume, as well as temperature of a gas. It can be expressed as
P1V1/T1 = P2V2/T2
Where
V1= initial volume= 20L
V2 = final volume= 10L
T1 = initial temperature= 100K
T2 = final temperature= 200K
P2=final pressure=
P1= initial pressure= 80pka
Making P2 subject of the formula from the eqn, we have
P2= (P1*V1*T2=)/(T1*V2)
If we substitute the values we have
P2= (80 × 20×200)/(100×10)
P2= 320pka
Hence, the new pressure is 320pka
I really need your guys help, I need to pass.
Answer:
Question 4 is 291.0346
Explanation:
PWEaseee help mweee ill mark brainliest I just need the answer pls and thank you amazing people
Order the following atoms from smallest to largest atomic radius: C, N, P
Answer:
N ∠ C ∠ P
Explanation:
Atomic radius:
It is define as the distance from nucleus of an atom the outer most electronic shell.
As we move down the group atomic radii increased because of increase of atomic number. Electrons are added in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
When we move from left to right across the periodic table electron are added in the same shell at the same time protons are also added in the nucleus hence positive charge is going to increase and this effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus and atomic radii decreases.
Carbon and nitrogen are present in period 2 while phosphorus is present in period 3 thus phosphorus has largest atomic radii. Carbon and nitrogen are present in same period but nitrogen is more right as compared to the carbon which means nitrogen has one more valence electron thus its size is smaller than carbon.
Values of atomic radii.
P = 98pm
C = 67pm
N = 65 pm
N ∠ C ∠ P
Apart from cost, give three reasons why steel should be recycled
Answer:
Well, acutally it shouldnt..but why it should be recycled is because 1. you can use it for many nessactities such as cars and blades, and bikes
You should also recycle it for, scrap parts! so just in case if you need recycled steel ya know where to get it
Lastly, you should recycle steel because of its value. If you recycle steel then melt it, and make well i dont know, a blade out it, you might have just made something, and then think, "Well that was fun and easy, i wanna use more recycled items to build or forge things
Explanation:
Hope this helps and pls mark brainlest!
Answer:
i think because its cause pollution
Explanation:
when making steel a lot of pollution goes in the atmosphere so if you recyle the the steel we may less pollution [ im only 12 so im sorry if this was wrong]
Of the three types of plate boundaries, which type is most likely to be associated
with pulling or tension forces?
transform
convergent
divergent
Balancing Equations
Fe + O2 --> Fe2O3
Answer:
4Fe + 3O2 --> 2Fe2O3
Explanation:
Type the correct answer in the box, Express the answer to three significant figures. Given: N2 + 3Cl2 + 2NC3, AH = 464 kJ/mol Use the given bond energies and the periodic table to calculate the energy change in the reaction. The AH when 85.3 grams of chlorine reacts in the given reaction is kilojoules.
Answer:
The given chemical reaction is:
Δ∑BE(reactants)-∑BE(products)
= {(941 kJ/mol) + (3 * 242 kJ/mol)} -[{2*(3*200 kJ/mol)}]
= 467 kJ/mol
Calculating the change in heat when 85.3 g chlorine reacts in the above reaction:
Moles of chlorine =
= 1.20 mol
Heat change when 1.20 mol chlorine reacts
=
Explanation:
Answer:
He is right tho not gone hold you
Explanation:
If you find a chemical in the lab and are unsure of
its identity, what is the best way to find out what it
is?
Answer:
C. read the label on the container
Explanation:
What information is found in an SDS? Check all that apply.
A. the identification of the chemical
C. the chemical and physical properties of the substance
D. the first-aid measures to take if an accident occurs involving the chemical
Answer:
C
Explanation:
just did it
The only way to see the far side of the moon is
Answer:
Only one side of the spherical Moon is ever visible from Earth it wasn't until 1959 when the Soviet Spacecraft Luna 3 orbited the Moon and sent pictures home that human beings were able to see the "far side" of the Moon for the first time. A phenomenon called tidal locking is responsible for the consistent view
Fun fact! <3
An apple, potato, and onion all taste the same if you eat them with your nose plugged
Answer:
:O Fr? Bet let me go get them lol
✧ Yes, since one of our senses are missing we won't really detect the taste.
Explanation: Think about it, we usually smell food and we can already tell if it's going to taste good or not. Looking or touching food doesn't always help to know if we will like the taste. ✧
Question 1
Identify the type of bonding for CaBr2
CaBr2 is an ionic bond. This is because the calcium gives up an electron to each of the chlorine atoms resulting in the calcium becoming Ca2+ ions...
Summarize the history of radioactivity by choosing the scientist(s) involved with each discovery.
conducted experiments with uranium-containing minerals and pure uranium.
came up with the term “radioactivity.”
showed that uranium in a mineral gave off radiation even without being exposed to the Sun.
discovered radium and polonium.
conducted experiments with fluorescent minerals and photographic plates.
Answer:
Marie and Pierre CurieMarie and Pierre CurieAntoine Henri BecquerelMarie and Pierre CurieAntoine Henri BecquerelExplanation: Correct on Edg 2020/2021.
WHICH COMPOUND HAS BONDS WITH THE LEAST DEGREE OF POLARITY (LEAST POLAR)?
Explanation:
H−S has least polarity in the bond because the electronegativity difference between H and S is the least.
After two alpha decays, Carbon-14 will become?
Answer:
Becomes Nitrogen-14
Explanation:
which element has two valence electrons in the s sublevel of the fourth energy level
what are all the populations of different species that live in the same area at the same time
Answer:
The answer is Community
Explanation:
When placed in distilled water, the pH of metal oxides will be?
Less than 7
Equal to 7
greater than 7
neutral
When placed in distilled water, the pH of metal oxides will be greater than 7. The correct option is C.
What are metal oxides?Metal oxides are crystalline solids containing both a metal cation and an oxide anion. In most cases, they react with water to form bases or with acids to form salts.
Metal oxides are compounds that contain two elements, namely a metal and an oxygen atom. Examples include sodium oxide (Na2O), magnesium oxide (MgO), calcium oxide (CaO), and others.
When metal oxides react with dilute acids, they form salt and water, demonstrating that they are basic.
Metal oxides are alkaline. When we dissolve them in water, we get solutions with pH values higher than 7. The reaction between a nonmetal and oxygen produces nonmetal oxides. Nonmetal oxides are highly acidic.
Thus, the correct option is C.
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ITEM BANK: Move to Bottom
Balance
Measured in Newtons
Measured in grams
Property of matter
Spring Scale
Weight
Both
Mass
Cugan 100
drag and drohte
Answer:
The scale reads the tension in the string. The tension in the string is 100 N. This is the force the string must exert up on either of the 100-N weights at either end of the string.
Nothing is moving, nothing is accelerating, so the net force on the spring is zero. Likewise, the net force on either of the 100-N weights is also zero. But that is another question. The spring scale does not measure the net force. The spring scale simply measures the tension, the magnitude of the force exerted by the string.
Explanation:
What happens when liquid changes to gas?
1.Added heat makes water molecules move fast enough to overcome the attraction
between them
2. Heat causes molecules to speed up and merge together (Which one?)
Answer:
#1
The temperature that this happens is called the freezing point and is the same temperature as the melting point. As more energy is put into the system, the water heats up, the molecules begin moving faster and faster until there is finally enough energy in the system to totally overcome the attractive forces.
Explanation:
#2
Heating a liquid increases the speed of the molecules. An increase in the speed of the molecules competes with the attraction between molecules and causes molecules to move a little further apart. ... A decrease in the speed of the molecules allows the attractions between molecules to bring them a little closer together.