Periodic Definition and 437 Threads

The periodic table, also known as the periodic table of elements, is a tabular display of the chemical elements, which are arranged by atomic number, electron configuration, and recurring chemical properties. The structure of the table shows periodic trends. The seven rows of the table, called periods, generally have metals on the left and nonmetals on the right. The columns, called groups, contain elements with similar chemical behaviours. Six groups have accepted names as well as assigned numbers: for example, group 17 elements are the halogens; and group 18 are the noble gases. Also displayed are four simple rectangular areas or blocks associated with the filling of different atomic orbitals.
The elements from atomic numbers 1 (hydrogen) to 118 (oganesson) have all been discovered or synthesized, completing seven full rows of the periodic table. The first 94 elements, hydrogen to plutonium, all occur naturally, though some are found only in trace amounts and a few were discovered in nature only after having first been synthesized. Elements 95 to 118 have only been synthesized in laboratories, nuclear reactors, or nuclear explosions. The synthesis of elements having higher atomic numbers is currently being pursued: these elements would begin an eighth row, and theoretical work has been done to suggest possible candidates for this extension. Numerous synthetic radioisotopes of naturally occurring elements have also been produced in laboratories.
The organization of the periodic table can be used to derive relationships between the various element properties, and also to predict chemical properties and behaviours of undiscovered or newly synthesized elements. Russian chemist Dmitri Mendeleev published the first recognizable periodic table in 1869, developed mainly to illustrate periodic trends of the then-known elements. He also predicted some properties of unidentified elements that were expected to fill gaps within the table. Most of his forecasts soon proved to be correct, culminating with the discovery of gallium and germanium in 1875 and 1886 respectively, which corroborated his predictions. Mendeleev's idea has been slowly expanded and refined with the discovery or synthesis of further new elements and the development of new theoretical models to explain chemical behaviour. The modern periodic table now provides a useful framework for analyzing chemical reactions, and continues to be widely used in chemistry, nuclear physics and other sciences. Some discussion remains ongoing regarding the placement and categorisation of specific elements, the future extension and limits of the table, and whether there is an optimal form of the table.

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  1. U

    Periodic Functions: Find Fundamental Period & Graph Solution

    Homework Statement What is the fundamental period of the expression sinx/sinx.can you guys please illustrate how to make its graph? Homework Equations Okay I know drawing graph can give me the period.Can the period be found by any other method? The Attempt at a Solution I'm told that the...
  2. SU403RUNFAST

    Sketching a periodic function and Fourier analysis

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  3. V

    How Do You Determine Values of a Periodic Function with Limited Data?

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  4. F

    I Question about fitting periodic data

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  5. Geek007

    Decomposition of apriodic and periodic signals

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  6. Y

    A Periodic Function Looks Like This Formula?

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  7. F

    Periodic Table Element Names: Latin vs. Germanic

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  8. Anithadhruvbud

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  9. Priyadarshini

    Periodic Table and oxidising agent

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  10. DrClaude

    7th period of the periodic table now complete

    http://www.iupac.org/news/news-detail/article/discovery-and-assignment-of-elements-with-atomic-numbers-113-115-117-and-118.html
  11. M

    Fourier series of periodic function

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  12. Karan Punjabi

    Explaining the Proton-to-Electron Ratio in the Periodic Table

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  13. E

    Power of first three harmonics of periodic signal

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  14. D

    Periodic motion -- Potential as a function of a non-linear Force(x)

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  15. H

    Are all damped oscillations periodic?

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  16. F

    Is a Bloch wave periodic in reciprocal space?

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  17. evinda

    MHB Solve Periodic Problem: Find Function $u \in C^2(\mathbb{R})$

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  18. **Mariam**

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  19. K

    Prove f(x) = sin(x^2) isn't periodic

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  20. Mister T

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  21. W

    Periodic Functions: Is Irrationality the Cause of Non-Periodicity?

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  22. Einj

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  23. A

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  24. D

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  25. D

    Sum of Two Periodic Orthogonal Functions

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  26. Q

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  27. N

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  28. S

    What exactly is periodic motion?

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  29. W

    Periodic Boundary Conditions proof

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  30. nusaiba mustafa

    What Are the Periodic Trends and Properties of Atomic Elements?

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  31. Greg Bernhardt

    Insights It's Elemental. The Periodic Table quiz - Comments

    Greg Bernhardt submitted a new PF Insights post It's Elemental! The Periodic Table Quiz Continue reading the Original PF Insights Post.
  32. Atlas3

    Can time be a periodic function in GRFE?

    I am learning more about the Einstein Filed Equations. I do not know how to evaluate them. Can someone tell me if time can be a periodic function in the equation for spacetime? i may not have that spacetime correctly stated. Can time periodically vary like a SIN function and still work in the...
  33. A

    Singular spectral analysis of periodic series with period L

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  34. R

    Is 5s2 5p4 in Group 17 and Period 6 on a Different Periodic Table?

    Homework Statement In the long form of periodic table, the valence shell electronic configuration of 5s2 5p4 corresponds to the element present in A. Group 16 and period 5 B. Group 17 and period 6 C. Group 17 and period 5 D. Group 16 and period 6 Homework Equations NA The Attempt at a...
  35. L

    Inelastic collision affecting periodic motion

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  36. S

    Question about the periodic table arrangement

    Hi, I'm new here. I'm actually studying the periodic table and while collectting the data on excel i noticed something. I wouldn't see it with the usual display of a periodic table but when you put it all in a sheet, ligns after ligns it become obvious to me. Argon Ar (noble gaz) is followed...
  37. Jewish_Vulcan

    Which mass number is shown on the periodic table?

    There are many different mass numbers for a given element known as isotopes. Are elements on the periodic table isotopes of their element? Why not use the average of all the mass numbers for an element?
  38. B

    Heat equation, periodic heating of a surface

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  39. arpon

    Energy conservation and periodic motion

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  40. I

    Mathematica Mathematica Ndsolve periodic boundary conditions

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  41. H

    Periodic trends and effective nuclear charge

    My book is trying to explain why atomic radii decreases as you move toward the right side of the periodic table because the effective nuclear charge increases. I understand why an increase in effective nuclear charge results in a smaller radius, but I don't know why the effective nuclear charge...
  42. J

    Electric field of periodic charge density.

    Homework Statement Find electrostatic field and potential created by a two-dimensional charge density: \rho \sin (kx) \cos (ky) \delta (z) at the distance d from the the plane z=0 where the charge is placed (taking into account that it is embedded in a three dimensional space). In your...
  43. D

    Meaning of total ground state energy in periodic DFT calculations

    Dear all, periodic DFT codes (e.g. VASP) effectively simulate an infinite crystal due to the periodic boundary conditions. However, the energy value that one obtaines at the end of a simulation if finite. Frankly, I'm quite confused right now. Is the energy to be understood 'per unit cell'...
  44. R

    Periodic Boundary Conditions and which Hamiltonian to use

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  45. E

    Convolution Dirac impulse and periodic signal

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  46. R

    What are the most reactive elements in the periodic table?

    What are the most reactive elements in the periodic table?
  47. bibo_dvd

    Periodic Complex exponential signal

    hello guys .. first of all , iam not sure that i should type this thread here . so excuse me for that in this problem i can understand the part until it's said that w=0 then x(t)=1, which is periodic for any value of T but i can't understand the part after that in the case of w is not equal...
  48. B

    Automotive Car Periodic Vibration/Modulation Captured with App - Some Questions

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  49. David Carroll

    Rope swinging with periodic radius changes

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  50. W

    Schrodinger in a weak periodic potential

    Hi, I have problems figuring out what both c-coefficients means. Can someone explain this in a conceptual way? Also, Vg and V-g are the coefficients of the Fourier series if you expand V, but what does it mean physically? Thanks in advance.
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