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3 years ago

How does the modern periodic table arrange elements?

Chemistry

2 answers:

mash [69]3 years ago

8 0

Answer: The elements are arranged according to the atomic numbers.

Explanation:

Elements in a periodic table are distributed in 7 Periods and 18 Groups.

The elements are distributed on the basis of increasing atomic numbers. They are arranged horizontally with increasing atomic number.

In earlier times, the periodic table was arranged according to average atomic mass which had many anomalies.

When elements are arranged according to atomic numbers, they followed a periodic pattern and thus similar elements can be categorized in the same group.

Thus, in modern periodic table, the elements are arranged according to increasing atomic numbers.

Norma-Jean [14]3 years ago

7 0

The elements are arranged in order of increasing atomic number. Vertical columns(called groups) contain elements with similar properties. Horizontal rows called periods elements with the same number of atomic orbitals(That's why Hydrogen and Helium are separated from the rest of the table).

Hope this helps:)

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What is the silver ion concentration in a solution prepared by mixing 425 mL 0.397 M silver nitrate with 427 mL 0.459 M sodium p

Lisa [10]

Answer:

0 M is the silver ion concentration in a solution prepared mixing both the solutions.

Explanation:

$molarity=\frac{\text{Moles of solute}}{\text{Volume of solution (L)}}$

Moles of silver nitrate = n

Volume of the solution = 425 mL = 0.425 L (1 mL = 0.001 L)

Molarity of the silver nitrate solution = 0.397 M

$n=0.397 M\times 0.425 L=0.1687 mol$

Moles of sodium phosphate = n'

Volume of the sodium phosphate solution = 427 mL = 0.427 L (1 mL = 0.001 L)

Molarity of the sodium phosphate solution = 0.459 M

$n'=0.459 M\times 0.427 L=0.1960 mol$

$3AgNO_3+Na_3PO_4\rightarrow Ag_3PO_4+3NaNO_3$

According to reaction, 3 moles of silver nitrate reacts with 1 mole of sodium phosphate, then 0.1687 moles of silver nitrate will recat with :

$\frac{1}{3}\times 0.1687 mol=0.05623 mol$ of sodium phosphate

This means that only 0.05623 moles of sodium phosphate will react with all the 0.1687 moles of silver nitrate , making silver nitrate limiting reagent and sodium phosphate as an excessive reagent.

So, zero moles of silver nitrate will be left in the solution after mixing of the both solutions and hence zero moles of silver ions will left in the resulting solution.

0 M is the silver ion concentration in a solution prepared mixing both the solutions.

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2 years ago

The enthalpy change for converting 10.0 g of ice at -25.0 °C to water at 90.0 °C is __________ kJ. The specific heats of ice, wa

Nina [5.8K]

AH1 = m * c1 * AT1 calculate this for ice (-25C to 0C) AH2 = AHfus(1 mole)=6.01 kJ = 6010 J AH3 = m *c3 * AT3 calculat this for water (0C to 100C) AH4 = AHvap(1mole)=40.67 kJ = 40670 J AH5= m * c5 * AT5 calculate this for steam (100C to 125C)
Sum ---- AH1+AH2+AH3+AH4+AH5
Data m=18g (1mole water)
c1=specific heat ice= 2.09 J/g K c3=specific heat water= 4.18 J/g K c5=specific heat steam= 1.84 J/g K
AT = (Tend - Tinitial) as this is a difference between temperatures it doesn't matter the units Celsius or Kelvin. Kelvin (K)=Celsius (C)+273.15
AT1 = 0C - (-25C)= 25C= 273.15K - 248.15K= 25K AT3= 100C - 0C = 100C= 100K AT5= 125C - 100C= 25C=25K

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2 years ago

You are planting flowers in large pots. You plan to plant flowers in 10 pots. 15 cups of potting soil will fill one pot. A bag o

dimaraw [331]

Answer:

I will need six (6) bags of potting soil

Explanation:

Since you plan on planting in 10 pots and need 15 cups of potting soil per pot, the total amount of potting soil you need (in cups) is 10 X 15 = 150 cups of potting soil.

We have that a bag contains 25 sups. to get the number of bags needed, we have to divide 150 by 25. This will give us 150 / 25 = 6 bags.

Therefore, I will need six (6) bags of potting soil

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3 years ago

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aleksandr82 [10.1K]

Takes place in USA and Mexico

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3 years ago

Read 2 more answers

What is the solution's freezing point: 15 g of CH4N2O (Molar mass = 60.055 g/mol) in 200. g of H2O? (Kf = 1.86 (°C·kg)/mol)

AURORKA [14]

Ok to answer this question we firsst need to fin the number of mol of Urea (CH4N2O). to do this we simply :

1 mol of urea =15/60.055 = 0.25mol

therefore 200g of water contain 0.25mol

the next step is to determine the malality of our solution in 200g of water, to do this we say:

200 g = 1Kg/1000g = 0.2kg

therefor 0.25mol/0.2Kg = 1.25mol/kg

and from the equation:

we know that i = 1

we are given Kf

b is the molality that we just calculated

therefore;

the solutions freezing point is -2.325°C

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1 year ago