name the group and period of an element having atomic number 21​

Answers

Answer 1

Answer:

The element in question here is Scandium, with an atomic number of 21. It is situated in Group 3 and Period 4 of the Periodic Table.

Explanation:

Hope this helped!

Answer 2
Scandium has an atomic value of 21 it is in group 3, period 4 of the periodic table

Related Questions

Suppose you wish to determine the order of the reaction. You initially measure a rate, r0, given some arbitrary concentration of reactants. You then proceed to double the amount of A in the reaction (keeping B the same) and find that the rate is now 2r0. In a reciprocal experiment, you double the amount of B (A same as initial) in the reaction and measure a rate of 8r0. What is the order of this reaction

Answers

Answer:

See explanation

Explanation:

Now taking A, we can see that if we double the amount of A while keeping the amount of B constant, the rate of reaction doubles, hence we can write;

2^n = 2^1

hence n =1

For B, when the amount of B is doubled while keeping the amount of A constant, the rate of reaction increases eight times. Hence we can write;

2^n = 8

2^n = 2^3

n=3

Hence this reaction has an overall order of 1 + 3 = 4

So we can write;

rate =k[A] [B]^3

a cup of liquid is measured to have a temperature of 290 Celsius, what would that be in the Kelvin scale

Answers

Answer:

795k

Explanation:

C÷5=k-273÷9

290÷5 = k - 273 ÷ 9

k = 795

the formula of calcium oxide is CaO. What is the formula of the ionic compound containing calium abd sulfate ions

Answers

Answer:

[tex]CaS[/tex]

Explanation:

Hello!

In this case, since calcium's oxidation state when forming ionic bonds is +2 and sulfur's oxidation state when bonding those bonds is -2, for the required formula we write:

[tex]Ca^{2+}S^{2-}[/tex]

Now, since they have the same charge number, we infer the ionic compound formed when they bond is calcium sulfide:

[tex]CaS[/tex]

Best regards!

. A student adds 50 mL of Lead (II) Nitrate solution to 50 mL of potassium iodide. Each
solution is colorless, but when these two liquids are mixed, a yellow precipitate is
observed. What has most likely happened in the experiment?

Answers

Answer:

after the reaction between Lead (II) Nitrate solution and potassium iodide occur Lead(II) iodide  was formed and it's yellow color.

Explanation:

Pb(NO3)2 + KI = KNO3 + PbI2

Which is one advantage of using a reflecting telescope instead of a refracting telescope?

Reflecting telescopes are less expensive.
Reflecting telescopes produce clearer images.
Reflecting telescopes require only concave lenses.
Reflecting telescopes usually take up less space.

Answers

Answer:

Reflecting telescopes take up less space, is the suitable answer.

Answer:

B, or 2: Reflecting telescopes produce clearer images.

Explanation:

Took the test

In a double replacement reaction, the ions of two compounds exchange places in an aqueous solution to form two new compounds.

True

False

Answers

Answer:

true

Explanation:

Answer:

True

Explanation:

In a displacement reaction, more reactive element displaces less reactive element. Whereas in a double displacement reaction there is exchange of ions of two compounds.

Which of the following statements is true about exothermic reactions?

Answers

Answer:

An Exothermic Reaction , gives off more heat, and a little energy to its surroundings.

this can helps us figure out that the answer is , C, More heat is given off into its products.

Explanation:

An atom has a mass number of 9 and 5 neutrons. What is its atomic number? A 19 B. 14 O c.4 D. 11 SN​

Answers

Answer:

[tex]\boxed {\boxed {\sf C. \ 4}}[/tex]

Explanation:

First, define some important terms.

Mass number: the sum of the nucleons (protons and neutrons) Atomic number: the number of protons

We know the mass number is 9. So, the sum of protons and neutrons is 9.

[tex]mass \ number =9[/tex][tex]protons + neutrons = 9[/tex]

We also know the atoms has 5 neutrons. Therefore, the rest must be protons.

[tex]protons + 5 \ neutrons =9[/tex]

Subtract the 5 neutrons from the overall mass number of 9.

[tex]protons = 9- 5 \ neutrons \\[/tex][tex]protons=4[/tex]

There are 4 protons, so the atomic number is also 4. This atom is beryllium.

dipole dipole bonds are covalent bond?​

Answers

Answer:

The polar covalent bond is much stronger in strength than the dipole-dipole interaction. The former is termed an intramolecular attraction while the latter is termed an intermolecular attraction. So now we can define the two forces: Intramolecular forces are the forces that hold atoms together within a molecule.

Explanation:

I have some things to point out:

#1: There is no such thing as "Dipole-dipole bonds", only Dipole-dipole interactions between molecules that share an unequal balance of electrons between their atoms.

#2: Intermolecular forces of attraction such as Dipole-dipole interactions are not considered as covalent bonds. Covalent bonds are rigid and are considered intramolecular forces of attraction (found within the molecule instead of between)

Hope I have helped you! Many thanks.

What happens to a rock formation that undergoes a repeated and frequent freeze and thaw cycle of water?

Answers

Answer:

Water from melting snow or rainfall infiltrates into cracks in rocks. ... As this process of freezing and thawing happens repeatedly, the rock begins to weaken and eventually breaks apart into angular fragments.

Explanation:

Water melting from snow or rainfall which infiltrates into cracks in rocks,  this is repeated process of freezing and thawing,  the rock begins to weaken and eventually breaks apart into angular fragments.

What are types of rock layers  ?

A rock can be formed due to the aggregation of mineral constituents in the earth’s crust and  it can be classified is based on different factors like Geological classification, Physical classification, Chemical classification.

Geological classification can be either Sedimentary rock formed by the deposition of sediments by the weathering of pre-existing rocks and it can be carried out by various agents like water, wind, gravity, etc.

Igneous rocks formed  by the  solidification of magma below the earth’s surface which is held together below the earth’s surface and unable to descend, when these magma cools down  and solidifies into igneous rocks.

Learn more about rock layer, here:

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Which part of the immune system can be "trained" using vaccines?

Answers

The adaptive immune system, because it is more specific to the foreign substances in the body and adapts to remove or fight them

15
Question 56 (1 point)
What is the name of the compound with the chemical formula SnSnO3?

Answers

Answer: sodium sulfite

Explanation:

The table shows four reactions.
Reactions
Reaction Equation
C₃ H8+ 50₂ 3C02 + 4H20
2Ca + O2- 2CaO
AgNO3 + NaCl
AGCI + NaNO3
CH3COOH + 202 - 2CO2 + 2H20
4
Which of the above reactions is an example of combustion of an Inorganic substance? (5 points)

Answers

Answer: 2

Explanation:

A combustion reaction must include O2 as a reactant.

An inorganic substance almost never includes carbon.

So, by process of elimination:

1. Carbon is a reactant = probably not

2. Has O2, no carbon = yes

3. O2 is not a reactant = no

4. Carbon is a reactant = probably not

An example of the combustion of an inorganic substance is:

2 Ca + O₂ ⇒ 2 CaO

We have 4 reactions and we want to determine which is an example of combustion of an inorganic substance.

What is combustion?

A combustion reaction is a reaction in which a substance reacts with oxygen gas, releasing energy in the form of light and heat.

What is the difference between organic and inorganic substances?

Organic substances always contain carbon while most inorganic substances do not contain carbon.

Let's consider the following reactions.

C₃H₈ + 5 O₂ ⇒ 3 CO₂ + 4 H₂O

This is a combustion reaction but C₃H₈ is an organic substance.

2 Ca + O₂ ⇒ 2 CaO

This is an example of the combustion of an inorganic substance.

AgNO₃ + NaCl ⇒ AgCI + NaNO₃

This is not a combustion reaction.

CH₃COOH + 2 O₂ ⇒ 2 CO₂ + 2 H₂O

This is a combustion reaction but CH₃COOH is an organic substance.

An example of the combustion of an inorganic substance is:

2 Ca + O₂ ⇒ 2 CaO

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Becky places a strip of metal into a clear liquid and they react. A has given off . The liquid is most likely which kind of substance?

Answers

Answer:

The liquid is likely to be a base e.g Sodium hydroxide solution or Ammonia solution

The liquid is likely to be a Base .

Acid and base

The terms acid and base describe chemical characteristics of many substances that we use daily. Acidic things taste sour. Basic or alkaline things taste soapy. Strong acids are corrosive and strong bases are caustic; both can cause severe skin damage that feels like a burn.  However, mild acids and bases are common and relatively harmless to us.

 2 H2O ⇌ 1 H3O+ + 1 OH-

Examples of bases are sodium hydroxide, calcium carbonate and potassium oxide. A base is a substance that can neutralize the acid by reacting with hydrogen ions. Most bases are minerals that react with acids to form water and salts.Basic substances react to aqueous solutions by accepting protons, giving away electrons, or releasing hydroxide ions. They neutralize acids by reacting with hydrogen ions to form salts and water. A base that dissolves in water is also known as an alkali.The scale has values ranging from zero (the most acidic) to 14 (the most basic). As you can see from the pH scale above, pure water has a pH value of 7. This value is considered neutral—neither acidic or basic.

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According to the collision theory, which is required for a high number of effective collisions? a very low amount of force from colliding molecules a very low amount of kinetic energy from colliding molecules molecular collisions that have very specific orientations molecular collisions with energy to overcome activation energy

Answers

Answer:

the answer is D

Explanation:

i answered c and got it wrong on edg... i hope this helps :)

According to the collision theory, molecular collisions that have very specific orientations are required for a high number of effective collisions.

What is collision theory?

Collision theory is used to predict the rates of chemical reactions, particularly for gases.

Based on the collision theory, a high frequency of effective collision is dependent on the molecular collisions that have very specific orientations.

The collision theory suggests that for reactions to occur, there must collision between reacting particles.

The number of collision is dependent on the number of collision per unit time as well as fractions of effective collision.

To attain effective collision, colliding particles must be properly oriented to give the desired product.

Hence, option C is correct.

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The greater the resistance, the less current there is for a given voltage.
Please select the best answer from the choices provided
True
False
❤️❤️❤️

Answers

Answer:

The answer is True.

What type of reaction occurs between an element and a compound?

Answers

Answer:

exothermic reaction

Explanation:

because it occurs in the presence of heat

PLEEAASE HELLLP AAAASSSASSSSSPPPPP​

Answers

Answer:

Concept: Chemical Analysis

Higher humidity indicates a higher concentration of water molecules and hence a higher statistical probability of rain.Hence Fred in Kentucky will need an umbrella tomorrow due to the humidity and stratus clouds.Give brainlist.

HELP ASAP DUE IN 5 MINUTES WILL GIVE BRAINLIEST
Energy is conserved within a system, meaning that forms of energy are either transferred or transformed as they interact with objects. Which of the statements below correctly describe how energy is transferred or transformed in daily life?
Group of answer choices

Kinetic energy transforms into thermal energy when a heating pad is turned on.

Electrical energy is transferred into light energy so that a flashlight generates light when it’s turned on.

Chemical energy in food is transformed into mechanical energy as our body rides a bicycle down the street.

Nuclear energy is transferred to electrical energy to provide electricity for our homes.

Answers

Answer:

i do believe it is C. Chemical energy in food is transformed into mechanical energy as our body rides a bicycle down the street. but if i am wrong plz don't come at me but i believe that is right

Explanation:

Answer:

i do believe it is C. Chemical energy in food is transformed into mechanical energy as our body rides a bicycle down the street. but if i am wrong plz don't come at me but i believe that is right

Explanation:

how can use a BIPHASIC LIQUIDS​

Answers

Answer:

BIPHASIC LIQUIDS are used ear cleaning, to softening the wax so that mild infections can be treated.

Explanation:

BIPHASIC LIQUIDS are liquids that contain two immiscible phases, one is suspension and the other is emulsion. In suspension, the finely solid are dispersed in a liquid or semi solidwhich is use for medicament

The emulsion consist of immiscible liquids, one is dispersed in globules.

They are used ear cleaning, to softening the wax so that mild infections can be treated.

it was believed that earth was a stationary object at the center of the universe all other objects in space without to go around earth which of these is a criticism of this idea

Answers

Answer: is that a question or

Explanation:

Answer:

its c

Explanation:

1
MS-LS1-1, MS-LS1-2
Structure and
Function of Cells
-, -
1. Which of the following is not stated in the cell
theory?
A. Cells are the basic unit of structure and
function in all living things.
B. Animal cells are generally more complex
than plant cells.
C. All living things are composed of cells.
D. All cells are produced from other cells.
Ok

Answers

Number b, because nothing mentions that:))

bond energy is the greatest for?​. a: Ch4 b: O2 c: N2 d: Cl2

Answers

It's answer is c. N2

The maximum bond energy is of N2 because N2 molecule is formed by 3 covalent bonds and O2 molecule is formed by 2 covalent bonds.

Hope it helps :)

which event would most likely lead to a thunderstorm HELP GIVING BRAINLIEST

Answers

Warm moist air jaisjsisksusjisjud

Answer:

A

Explanation:

i got right

HELPPP PLEASEEE

is this
1: radiation
2: conduction
3: convection

Answers

Number 2: Conduction.

This is an example of #2, conduction.

Conduction is the process where heat energy is transmitted through collisions between atoms or molecules.

Molecular orbital diagram for Fe.

Answers

ANSWER;

1s22s22p63s23p63d64s2

EXPLANATION;

Molecular orbital diagram for Fe.

In writing the electron configuration for Iron the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons for Iron go in the 2s orbital. The next six electrons will go in the 2p orbital. The p orbital can hold up to six electrons. We'll put six in the 2p orbital and then put the next two electrons in the 3s. Since the 3s if now full we'll move to the 3p where we'll place the next six electrons. We now shift to the 4s orbital where we place the remaining two electrons. After the 4s is full we put the remaining six electrons in the 3d orbital and end with 3d6.

Therefore the Iron electron configuration will be 1s22s22p63s23p64s23d6.

Note that when writing the electron configuration for an atom like Fe, the 3d is usually written before the 4s. Both of the configurations have the correct numbers of electrons in each orbital, it is just a matter of how the electronic configuration notation is written

Therefore we have 1s22s22p63s23p63d64s2

a sample of helium gas is in a sealed rigid container

Answers

is there a question or no? im confused.

What’s the question?

Spheres of Earth Assignment Active Analyzing Sphere Interactions Explain how Earth's spheres may be affected by the droughts brought on by El Niño. Sometimes, the surface of the Pacific Ocean warms up, causing changes in the weather in some areas. This phenomenon is called El Niño. El Niño causes the amount of rainfall in some parts of the United States and South America to increase. It also causes droughts to occur in Southeast Asia and Australia. Droughts occur when an area receives less rain than it normally does over a certain period.


help me on this question please. it is 7th grade science​

Answers


During El Niño, changes in wind and ocean current patterns result in warm waters stretching across the whole Pacific Ocean. This extra heating causes changes in wind patterns, which causes atmosphere to react and change all the way from the ground to the edge of space around Earth.

you have a friend who is using a recipe for flat from american cookbook you notice that he set your over temperature at 175F° what you advise him to do?​

Answers

Answer:

I will give them advice, that do the power of flame low....

Explanation:

thanks.

ANSWERS PLEASE HELP 20 MINUTES LEFT????!!!!?!!???

Answers

Answer:

Explanation:

b

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