why is
helium number 2 (the second element)
and beryllium number 4 (the fourth
element) on the periodic table ?

Answers

Answer 1

Answer:

See note in Explanation

Explanation:

The modern periodic table of the elements is arranged in order of increasing atomic numbers which is also in terms of the number of protons in the nucleus. That is, for any element listed on the periodic table its atomic number equals the number of protons in the nucleus. Thus, the element with 2 protons in its nucleus would be element #2 (Helium), element #3 (Lithium) has 3 protons in its nucleus and element #4 (Beryllium) has an atomic number 4 and contains 4 protons in its nucleus.

Also, this arrangement of elements finds that elements below elements 2, 3 & 4, Neon #10; sodium #11 & magnesium #12 have similar chemical and physical properties as does elements #2, #3 & #4. Such gives rise to the 'Periodic Law' => the chemical and physical properties of the elements is a periodic function of their atomic number (or, number of protons in the nucleus).


Related Questions

What types of radiation cause the parent isotope to change into a different element?

Answers

Answer:

Beta decay is most common in elements with a high neutron to proton ratio. Gamma decay follows the form: In gamma emission, neither the atomic number or the mass number is changed. A high energy gamma ray is given off when the parent isotope falls into a lower energy state.

Explanation:

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TOPICAL ASSINMENT 2
1. If 25cm' of O.IM H,SO, solution neutralised a solution containing 1.06g anhydrous sodium carbonate in
250cm. of solution, calculate the molarity and the volume of the sodium carbonate solution used. (3mks)​

Answers

The molarity = 0.04 M

The volume = 6.25 ml

Further explanation

Given

25cm³ of 0.1 M H₂SO₄

1.06g Na₂CO₃ in  250cm³ of solution

Required

the molarity and the volume of Na₂CO₃

Solution

Molarity of  Na₂CO₃ :

[tex]\tt \dfrac{1.06/106~mol}{0.25~L}=0.04~M[/tex]

Reaction

H₂SO₄ + Na₂CO₃ ⇒Na₂SO₄ + H₂O + CO₂

mol H₂SO₄ = 25 x 0.1 = 0.25 mlmol= 2.5 x 10⁻⁴ moles of  Na₂CO₃

The volume of solution used :

[tex]\tt V=\dfrac{n}{M}=\dfrac{2.5.10^{-4}}{0.04}=6.25.10^{-3}~L=6.25~ml[/tex]

Help me asap it’s for my chem

Answers

1 is oxygen
2 is c=1 O=2
3 is 10
4 is 4 C 12 H
5 is 4 Na 2S 8 O

Plz help!

What must change in order to change the amount of power?

Answers

Answer:

Mass

Explanation:

atoms or helium nickel would represent _____

Answers

Answer:

they represent their own atoms

Answer:

Elements

Explanation:

All matter is involved in motion of some kind. True or false

Answers

Answer:

true

Explanation: all matter down to the molecular or even atomic level has a constant vibration and movement. The only time that any matter could stop moving would be at absolute zero.

Where must you be standing if the Sun appears to be directly overhead at noon?
O A. At the South Pole
O B. At the North Pole
O C. At a point somewhere along the prime meridian
O D. At a point somewhere along the equator​

Answers

Answer:

D

Explanation:

at a point somewhere along the equator

In the case when the Sun appears to be directly overhead at noon should be along with the equator.

What is the equator?

It is considered to be the imaginary line that should be arounded with the middle of the planet or the celestial body. It is halfway that lies between the  North Pole and the South Pole, at 0 degrees latitude. In the equator, it divides the planet into a Northern Hemisphere and a Southern Hemisphere

Therefore, based on the above explanation, the option d is correct.

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EZ MODE -_- What could you do in an experiment to get more accurate results?  Change two of your variables. Only make observations that involve sight. Only use new materials. Perform repeated trials​

Answers

Answer:

they change the object hehehehe

Answer:

D. Perform repeated trials.

Explanation:

I did the exam and got it correct :D!

A family consumes 2.5 gallons of milk per week. How many liters of milk do they need to buy for one month? (Assume there are exactly 4 weeks in 1 month) SHOW WORK

Answers

Answer:

37.85 liters

Explanation:

they need 10 gallons for a month (2.5*4)

after that, convert gallons to liters (conversion to liters= 3.785)

10*3.7585= 37.85

Why do scientists often use bacteria to produce medicines?​

Answers

Answer:

Bbbbb eg2020

Explanation:

Bbbbb

Yes they do because its their job


Which formula compares a sample of a gas under two different conditions of pressure and volume, if the temperature is constant?

⚪︎ x/y = k
⚪︎ xy = k
⚪︎ PV = k
⚪︎ V/T = k
⚪︎ P1V1 = P2V2

Answers

Answer:

Explanation:

V/t

how many moles are in 100.0 g of gold?

Answers

Answer:

196.96655

Explanation:

The answer is 196.96655. I assume you are converting between grams Gold and mole. The molecular formula for Gold is Au. The SI base unit for the amount of substance is the mole.

The quantity present in an atom or molecules of a given substance is called moles it is written as mol and is calculated with the help of molar mass and mass of the given substance.

0.507699 mol is present in the 100 gm of gold.

Moles of gold can be calculated by:

Given,

Mass (m) = 100 gmThe atomic weight of Au (M) = 196.967

The formula for calculating moles is:

[tex]\rm Moles (n) = \dfrac{Mass}{Molar \;mass}[/tex]

Substituting values in the formula:

[tex]\begin{aligned}\rm n & = \dfrac{100}{196.967}\\\\ & = 0.507699 \;\rm mol\\\\& = 0.5077\;\rm mol\end{aligned}[/tex]

Therefore, 0.5077 mol is present in 100 gm of gold.

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An atom has 38 protons and 42 neutrons it is ?

Answers

Answer:

The answer is, Strontium

Answer:

Name                         Molybdenum

Atomic Mass                95.94 atomic mass units

Number of Protons 42

Number of Neutrons 54

Number of Electrons 42

Explanation:

What happens when the number of electrons and protons inside of an atom are Not equel?

Answers

Hello, It's me Moriah Elizabeth!

Answer:

When the number of electrons does not equal the number of protons, the atom is ionized.

Replication, Transcription, and Translation Chart
Please answer


DNA Replication:

1。Template Strand: Start with this nucleotide chain.

TACCCTTGAATAAAAAATCTCTGTTTGGTCGGTATTGTTGAAATC



2。Complementary DNA Strand: Write directly below template strand.


Transcription:

3。mRNA Strand: Write the complementary mRNA strand from the DNA template strand (#1).



Translation:

4。Anticodon: Write the anticodon sequence to match the mRNA strand (#3).



5。Protein Synthesis: Write the mRNA sequence that is complementary to the anticodons. Meaning the opposite code of the anticodons (#4).



6。Amino Acid Sequence: Create the amino acid sequence from protein synthesis using 3 letter abbreviation for amino acids (#5).

Answers

I can help with 1, 2, 3, and 4... 5 and 6, I don't understand.

Template sequence : TACCCTTGAATAAAAAATCTCTGTTTGGTCGGTATTGTTGAAATC

Complement sequence : ATGGGAACTTATTTTTTAGTGTCAAACCAGCCATAACAACTTTAG

mRNA sequence : AUGGGAACUUAUUUUUUAGAGACAAACCAGCCAUAACAACUUUAG

Anticodon sequence : AUG-GGA-ACU-UAU-UUU-UUA-GAG-ACA-AAC-CAG-CCA-UAA-CAA-CUU-UAG

(not 6) Protein synthesis : START-Gly-Thr-Tyr-Phe-Leu-Glu-Thr-Asn-Gin-Pro-Stop

please help me I will give brainesty if your right ​

Answers

Answer:

Sunlight

Explanation:

My science teacher has told us that plants need the sun to photosynthesis. And even though their is a lot of sun, they need to compete for it still.

A student spends 4.5 hours studying for a test. How much time is this equivalent to in seconds
Select one:
a)2,700 seconds
b)16,200 seconds
c)270 seconds
d)6,480 seconds

Answers

the answer is: b)16,200 seconds :)

explain how to find the mass of water. show your calculations as well​

Answers

Answer:

You can find the mass of water by multiplying the density of water by its volume.

mass = Density x volume

Explanation:

It is very easy to find the mass of water once you know the formula of density. "Density" refers to mass per unit volume.

Density (ρ) = [tex]\frac{mass}{volume}[/tex]

Therefore, mass = ρ x volume

The density of water is 1 kg/L.

For example, if the volume of water is 500 ml, then you can get its mass by multiplying 500 ml by 1 kg/L.

Let's convert 500 ml to Liter first.

500 ml x [tex]\frac{1 L}{1,000 ml}[/tex] = 0.5 L

Now, let's compute.

mass = ρ x volume

mass = 1 kg/L x 0.5L

mass = 0.5 kg

The mass of a 500-ml water is 0.5 kg.

What is the mass of 2.486 * 10^{24} atoms of neon?
Select one:
a)83.33 g Ne
b)0.2046 g Ne
c)8.333 g Ne
d) 4.130 g Ne

Answers

Answer:

The answer is A 83.33 g Ne

Explanation:

Used Avogadros Law

which description shows copper at rtp?
a) stationary and closed together
b) stationary and randomly arranged
c)vibrating and in a regular arrangement
d) vibrating and in a random arrangement

Answers

Answer:

c)vibrating and in a regular arrangement

Explanation:

Copper is a chemical element represented by the symbol Cu and having atomic number 29. Copper is a transition metal which means its subshells are not completely filled and that is why they are vibrating in the room temperature. But copper is a solid at room temperature with regular arrangement of atoms.

Hence, the correct answer is "c)vibrating and in a regular arrangement".

5(a) Consider the following schemes
Petroleum
>petroleum fractions
Higher petroleum fractions 1 , petrol + x
X + Y MI >CH,CICH,CI
nX"V (CH2 - CH2 - CH2-CH2)n
(i) State the type of reaction involved in I to IV​

Answers

Answer:

is number 1

Explanation:

cause i know

There is an equal number of protons and __________ in a neutral atom.
A. electrons
B. neutrons
C. protons
D. elements.

Answers

the answer is electrons

Based on the information in the table, which two elements are most likely in the same group, and why?

Answers

The answer would be Bismuth and Nitrogen because they have the same number of valence electrons. Groups in the periodic table are arranged in columns. When it comes to neutral atoms, the number of valence electrons it has is equal to the main group of that element.

For the reaction C+2H 2 —->CH 4 calculate the percent yield if 98 g of methane is produced when 100. g of carbon reacts with an excess of hydrogen?

Answers

The percent yield : 73.5%

Further explanation

Given

Reaction

C+2H₂⇒CH₄

Required

The percent yield

Solution

mol of Carbon(as a limiting reactant) :

[tex]\tt \dfrac{100}{12}=8.3[/tex]

mol CH₄ based on C, and from equation mol ratio C : CH₄, so mol CH₄ = 8.3

Mass of Methane(theoretical yield) :

[tex]\tt mass=mol\times MW\\\\mass=8.3\times 16=133.3~g[/tex]

[tex]\tt \%~yield=\dfrac{actual}{theoretical}\times 100\%\\\\\%yield=\dfrac{98}{133.3}\times 100\%=73.5\%[/tex]

What is the relationship between the circulatory and respiratory systems?
A. They work together to store the waste that blood collects from the body.
B. The circulatory system provides oxygen that the respiratory system uses to fill the lungs
C. The respiratory system provides blood that the circulatory system uses to transport nutrients.
D. They work together to supply oxygen to tissues and rid the body of carbon dioxide​

Answers

Answer:

The circulatory and respiratory systems work together to circulate blood and oxygen throughout the body. Air moves in and out of the lungs through the trachea, bronchi, and bronchioles. Blood moves in and out of the lungs through the pulmonary arteries and veins that connect to the heart

Explanation:

This should help you out

I think it’s (A) I’m not sure

What does bananas batteries and people have in common

Answers

Simple, humans share 60% of DNA with bananas. That means that you are asking the similarities to humans and batteries which means the answer is that they both have energy or can be used as ‘portable energy.’

Given the following information:
Heat of sublimation of Li(s) = 166 kJ/mol
Bond energy of HCl = 427 kJ/mol
Ionization energy of Li(g) = 520. kJ/mol
Electron affinity of Cl(g) = -2349 kJ/mol
Lattice energy of LiCl(s) = -2829 kJ/mol
Bond energy of H₂ = -432 kJ/mol
Calculate the net change in energy for the following reaction:
2Li(s) + 2HCl(g) --> 2LiCl(s) + H₂(g)

Answers

Answer:

Ya'll should really practice more because things like these are easy

Explanation:

You guys need to practice more since stuff like this are pretty simple.

What is net change?According to the net change theorem, the ultimate value of a quantity equals the beginning value plus the integral of the rate of change when a quantity changes. The net change can be positive, negative, or zero.The term "Net Change in Cash" indicates how much Cash and Cash Equivalents changed in value during the reporting period. It is the main punchline of the Cash Flow Statement. Net Cash Change quantifies how much the value of Cash and Cash Equivalents changed during the reporting period. The main punchline on the Cash Flow Statement is this. When using net cash as a barometer to determine a company's financial health, it is critical to analyse what activities contribute to positive or negative net cash.

To learn more about net change refer to:

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what is a substrate

Answers

Answer:

a substrate is surface or material on or from an organism lives, grows, or obtains its nourishment.

Explanation:

Hey I hope this helps.....

How many grams of lithium chloride, molecular mass 42.5, are dissolved in water to make 500 mL of a 0.450 M solution?

A) 9.56g
B) 42.50g
C)21.25g
D)47.22g

Answers

Answer:

9.5625 gram

Explanation:

Molarity = mass in gram ÷ molar mass × volume in dm3

Mass in gram = molarity× molar mass × volume of solution in dm3

Mass in gram = 0.450×42.5×0.5=9.5625 g

What is the momentum of a bird with a mass of 2 kg flying at 9 m/s? *

Answers

Answer:

18 kg.m/s

Explanation:

The momentum of an object can be found by using the formula

momentum = mass × velocity

From the question we have

momentum = 2 × 9

We have the final answer as

18 kg.m/s

Hope this helps you

Other Questions
Nobody wants to answer my questions for brainliest Do the boyz got me do? Another name for 3/3 isOA) 0OB) 3OC) 1 Read the excerpt from "On Becoming an Inventor" by Dean Kamen.I decided to put his entire machine shop in our basement, but there were two problems... One, his shop wouldn't fit in our basement, and two, there was no way the lathe, weighing fifteen hundred pounds, and the milling machine, weighing two thousand pounds, could be carried into the basement. I solved this problem by hiring a contractor to dig a large hole, break open a wall of the basement, enclose the addition with concrete, and add a roof that could be used for building an outside deck to the house. I also enlarged my mother's kitchen and pantry. I now had the entire machine shop in our basement. At the time I was making enough money from my electronic devices to pay for all of this.What conclusion can be drawn from the details in this excerpt?Kamen's family did not appreciate the enlargement of their basement.Kamen's mother had complained about the size of her kitchen and pantry.Kamen's idea to enlarge the basement benefited both his work and his family.Kamen's machine shop still did not fit into the newly enlarged basement. Eric rented a truck for one day the base fee was 16.95 for additional charge of .76 cents for each mile driven eric had to pay 152.23 when he returned the truck how many miles did he drive Explain how the aperture geometry relates to thediffraction pattern. HELPP !!! with 1 and 2 PLEASE ANSWER FASTOn 1 September, Leila starts to go swimming every day.She swims 30 lengths of the swimming pool every day. The swimming pool is 20m long.Work out the date when Leila has swum a total of 10 km. Pls help i need to fnsh 2) A big league pitching coach tries to limit his pitchers to 110pitches per game. If the pitcher has already thrown 52pitches, write and solve an inequality to find how many morepitches he can throw before reaching the limit. What continent is northwest of South America? A government where one person has absolute power is ...? A) an aristocracy B) a confederation C) A dictatorship D) a republic HURRY PLEASE 2. Why is the vagina called the birth canal?Ait is pyramid in shape.B. it is where the urine passesC. It receives the spermD. The new born baby passes out from it pls, help hurry! a-9and explain pls Write an Inequality to represent a graph. Stephanie spends $15 each month to belong to a photography club. As a member of the club she can develop rolls of film for $2.50 each. Write and solve an equation to find the total amount Stephanie will spend this month if she develops 5 rolls of film. What is the definition of detective skillsas used in this sentence?Using dazzling detective skills, geologists created a calendar of geologic time.Athe ability to study dinosaursBthe ability to solve crimesCthe ability to figure out the pastDthe ability to search for bones Write a linear equation for the table above. Use y=mx+b format A scientist uses a submarine to study ocean life she begins at C level which is at an elevation of 0 feet then she travel straight down for 90 seconds at a speed of 3.5 ft./s then she then travels directly up for 30 seconds how do you speed of 2.2 ft./s after this 120 seconds period how much time in seconds will it take for the sciences to travel back to see if level at the submarines maximum speed of 4.8 ft./s In the expression -3g + 12, how many terms are in the expression? *1234Which expression has three terms? *5x + kr3ab6 + x - 2y4p + 2 Why did Sangappa feel sad?