Perkembangan Sistem Periodik Unsur
Summary
TLDRThis script outlines the evolution of the periodic table, detailing significant contributions by scientists like Lavoisier, Dobereiner, Newlands, and Mendeleev. It highlights Lavoisier's categorization of 33 elements, Dobereiner's Triad theory, Newlands' law of octaves, and Mendeleev's predictive table with placeholders for undiscovered elements. The script also mentions Meyer's valency-based table and Moseley's discovery of atomic numbers, which refined the periodic system into its modern form.
Takeaways
- đ There are 118 elements, both natural and synthetic, that have been discovered and validated by the International Union of Pure and Applied Chemistry (IUPAC), and are included in the modern periodic table.
- đ Elements are arranged in the periodic table according to their atomic number, electron configuration, and chemical properties.
- đ The modern periodic table is a result of the evolution of earlier systems of classifying elements.
- đ In 1789, Antoine Lavoisier categorized 33 substances that could not be further decomposed into four categories based on their chemical properties: gases, nonmetals, metals, and earths.
- đŹ Around 1829, Johann Wolfgang Dobereiner grouped elements into triads based on their properties and relative atomic masses, noting that the middle element had properties between the first and third, and its atomic mass was close to the average of the other two.
- đ John Newlands, in 1864, noticed a pattern where every eighth element had similar properties to the first, a pattern he called the Law of Octaves, but this only applied to lighter elements and had some inaccuracies.
- đ In 1869, Dmitri Mendeleev published a periodic table organized by increasing relative atomic mass, predicting properties of undiscovered elements and leaving gaps for them, which were later found to align with his predictions.
- đ§ Mendeleev's system had flaws, such as elements being misplaced based on atomic mass and some elements with larger masses being placed before those with smaller ones.
- đŹ Julius Lothar Meyer also independently developed a periodic table, observing a relationship between atomic mass and chemical properties, and arranging elements by both increasing atomic mass and valency.
- đ In the 1930s, Henry Moseley discovered that the atomic number, determined using X-rays, determines the chemical properties of an element, leading to a more accurate periodic table arrangement.
- đ The modern periodic table is a culmination of these developments, with elements arranged by increasing atomic number, leading to periodic repetition of chemical properties.
Q & A
How many elements have been discovered and validated by the International Union of Pure and Applied Chemistry?
-As of the time mentioned in the script, 118 elements have been discovered and validated by the International Union of Pure and Applied Chemistry.
What are the modern periodic table's elements arranged according to?
-The elements in the modern periodic table are arranged according to their atomic number, electron configuration, and chemical properties.
Who was the first scientist to categorize elements based on their chemical properties?
-Antoine Lavoisier was the first scientist to categorize elements based on their chemical properties in 1789.
What were the four categories that Lavoisier used to classify elements?
-Lavoisier classified elements into four categories: gases, nonmetals, metals, and earths.
What was the main limitation of Johann Wolfgang Dobereiner's triad system?
-The main limitation of Dobereiner's triad system was that it only worked for a limited number of elements and did not accommodate newly discovered elements that did not fit into the triads.
What was John Newlands' discovery regarding the periodicity of elements?
-John Newlands discovered that the properties of elements repeat every eight elements, a pattern he called the 'law of octaves.'
How did Dmitri Mendeleev's periodic table differ from previous systems?
-Mendeleev's periodic table was arranged not only by increasing atomic mass but also by the periodic repetition of properties, and he predicted the existence and properties of elements that were yet to be discovered.
What were the shortcomings of Mendeleev's periodic table?
-Mendeleev's periodic table had shortcomings such as elements being misplaced based on atomic mass and some elements with similar properties being placed in different groups.
Who discovered the positive charge in the atomic nucleus, and what was its significance?
-Clara Terpaut discovered the positive charge in the atomic nucleus in the 1930s, which was significant as it helped understand the structure of the atom and the nature of chemical bonding.
How did Henry Moseley's discovery of atomic numbers influence the periodic table?
-Henry Moseley's discovery of atomic numbers showed that the chemical properties of elements are a periodic function of their atomic numbers, leading to a more accurate arrangement of the periodic table.
What is the significance of the modern periodic table's arrangement?
-The modern periodic table's arrangement is significant because it reflects the periodic nature of chemical properties based on atomic number, which has been validated by the discovery of new elements and advancements in atomic theory.
Outlines
đŹ Historical Development of the Periodic Table
This paragraph delves into the historical development of the periodic table, highlighting the contributions of various scientists. It starts with the discovery of 118 elements, both natural and synthetic, which are validated by the International Union of Pure and Applied Chemistry and organized into the modern periodic table. The elements are grouped by atomic number, electron configuration, and chemical properties. The paragraph then explores the early classification by Antoine Lavoisier in 1789, who listed 33 elements and categorized them into four groups based on their chemical properties. It also mentions the work of Johann Wolfgang Dobereiner, who grouped elements into triads based on their properties and relative atomic mass. The paragraph continues with the contributions of John Newlands, who observed a pattern of properties repeating every eighth element, and Dimitri Mendeleev, who is credited with creating the first comprehensive periodic table arranged by increasing atomic mass and predicting the properties of yet undiscovered elements. The limitations of Mendeleev's system are also discussed, such as the misplacement of elements and the lack of uniformity in grouping elements with similar properties.
đ Refinements and Modern Understanding of the Periodic Table
The second paragraph focuses on the refinements and advancements in the understanding of the periodic table. It discusses Julius Lothar Meyer's work, who not only organized elements by increasing atomic weight but also grouped them according to their valency. The paragraph then highlights the discovery of the positive charge in the atomic nucleus by Clara Terpstra and the significant contribution by Henry Moseley, who determined the atomic number of elements using X-rays. Moseley's findings led to the realization that the chemical properties of elements are periodic functions of their atomic numbers. This understanding led to the development of the modern periodic table, where elements are arranged in order of increasing atomic number, resulting in a more accurate and systematic representation of the periodic table as we know it today.
Mindmap
Keywords
đĄPeriodic Table
đĄAtomic Number
đĄElectron Configuration
đĄChemical Properties
đĄAntoine Lavoisier
đĄTriads
đĄOctave
đĄDmitri Mendeleev
đĄAtomic Mass
đĄHenry Moseley
đĄPeriods and Groups
Highlights
A total of 118 elements, both natural and synthetic, have been discovered and validated by the International Union of Pure and Applied Chemistry.
Elements are arranged in the periodic table according to atomic number, electron configuration, and chemical properties.
The modern periodic table categorizes elements into vertical groups and horizontal periods.
Each box in the periodic table contains information about the element's atomic number, symbol, and name.
The periodic table's organization has evolved from earlier systems.
Anton Lavoisier in 1789 listed 33 elements that could not be further decomposed.
Lavoisier grouped elements into four categories based on their chemical properties: gases, nonmetals, metals, and earths.
Lavoisier's categorization included light and heat as elements, considering them as matter.
Johann Wolfgang Dobereiner in the 1820s grouped elements into triads based on their properties and relative atomic mass.
Dobereiner's triads showed that elements had properties and atomic masses that were intermediate between the first and third elements.
John Newlands in 1864 noticed a pattern where every eighth element had properties similar to the first in a series.
Mendeleev's periodic table, introduced in 1869, arranged elements by increasing atomic mass and predicted properties of undiscovered elements.
Mendeleev left gaps for undiscovered elements and accurately predicted their properties when they were later found.
Meyer developed a periodic table based on atomic volume and valency, grouping elements with similar properties.
Clara Terpaut discovered the positive charge in the atomic nucleus in the 1930s.
Henry Moseley used X-rays to determine the atomic number of elements, showing that chemical properties were periodic functions of atomic number.
Moseley's work led to a better-organized periodic table that is similar to the modern system.
Transcripts
Hai sampai saat ini sudah ditemukan 118
unsur baik Unsur alami maupun sintetis
unsur-unsur yang sudah ditemukan dan
divalidasi oleh persatuan internasional
kimia murni dan terapan kemudian
dimasukkan ke dalam sistem periodik
unsur yang disesuaikan dengan nomor atom
konfigurasi elektron dan keberulangan
sifat kimia dalam tabel periodik modern
unsur-unsur dikelompokkan dalam lajur
vertikal atau yang disebut golongan dan
lajur horizontal atau yang disebut
periode setiap kotak dalam tabel
periodik unsur memuat informasi mengenai
nomor atom lambang dan nama unsur serta
masyarakat umum relatif
Hai pengelompokan unsur-unsur dalam
suatu sistem periodik mengalami
perkembangan dari masa kemasa sistem
periodik unsur yang sekarang merupakan
hasil dari perkembangan sistem periodik
unsur dari ilmuan-ilmuan sebelumnya jadi
Bagaimana perkembangan sistem periodik
unsur hingga tersusun tabel periodik
seperti sekarang ini Mari kita lihat
kembali sejarah pengelompokan unsur yang
dilakukan oleh Anton labuha cie ketika
tahun 1789 bahwa Sio dalam bukunya
membuat daftar 33 unsur atau zat yang
tidak dapat diuraikan lebih lanjut
lavoisier mengelompokkan dalam empat
kategori berdasarkan sifat kimianya
yaitu gas non logam logam dan tanah
Hai pengelompokan unsur atau zat menurut
lafayette dapat dituliskan seperti
berikut dalam pengelompokan unsur ini
fasih masih menyertakan cahaya dan kalor
sebagai sebuah unsur atom zat karena
dianggap sebagai materi Selain itu
beberapa zat dalam tabel periodik
lavoisier ternyata masih bisa diuraikan
lebih lanjut sekitar tahun 1820 9
seorang kimiawan asal Jerman Johann
wolfgang Dobereiner mengelompokkan unsur
dalam sebuah Triad berdasarkan sifat
unsur dan massa atom relatifnya menurut
Dobereiner dalam satu Triad unsur kedua
mempunyai sifat-sifat yang berada
diantara unsur pertama dan ketiga serta
memiliki massa atom yang relatif sama
dengan massa rata-rata unsur pertama dan
ketiga memberikan
Hai jika kita ambil contoh massa atom
natrium maka massa atomnya akan sama
atau mendekati rata-rata dari massa atom
litium dan kalium
Hai namun dalam konsep Triad yang
dikemukakan oleh Gubernur ini ada
beberapa kelemahan yaitu ada unsur yang
tidak tergolong dalam triac namun
memiliki sifat yang mirip dengan pria
tersebut Selain itu hanya ada lima Triad
yang teridentifikasi unsur-unsur yang
baru ditemukan tidak cocok dalam
pengelompokan Riyadh kemudian sekitar
tahun 1864 seorang kimiawan asal Inggris
John newlands mengelompokkan unsur
berdasarkan kenaikan massa atom relatif
n menemukan pola yang menunjukkan bahwa
sifat setiap suatu unsur akan berulang
pada unsur kedelapan unsur kedua akan
memiliki kemiripan sifat dengan unsur
kesembilan dan seterusnya sifat unsur
berulang setiap satu oktaf
Hai sistem periodik unsur ini pun
memiliki kelemahan yaitu hanya berlaku
untuk unsur dengan massa atom kecil
Selain itu terdapat beberapa unsur yang
ditempatkan dalam satu slot walaupun
memiliki sifat yang berbeda setelah
unsur-unsur yang ditemukan semakin
banyak pengulangan sifat ini tidak
selalu terjadi pada unsur kedelapan pada
tahun 1869 ahli kimia Rusia bernama
Dimitri Mendeleev mengemukakan tabel
periodik yang ia susun berdasarkan
kenaikan massa atom Mendeleev menyatakan
bahwa sifat tertentu akan berulang
secara periodik apabila unsur-unsur
disusun berdasarkan kenaikan massa atom
relatifnya Mendeleev selanjutnya
menempatkan unsur-unsur dengan kemiripan
sifat pada satu lajur vertikal yang
disebut golongan
Hai unsur-unsur juga disusun berdasarkan
kenaikan massa atom relatifnya dan
ditempatkan dalam satu lajur yang
disebut periode
Hai yang menarik dalam tabel periodik
ini adalah Mendeleev berani menyediakan
beberapa tempat kosong untuk unsur-unsur
yang belum ditemukan Mendeleev juga
memprediksi sifat-sifat unsur yang belum
diketahui tersebut pada perkembangan
selanjutnya beberapa unsur yang
ditemukan ternyata sesuai dengan
prediksi Mendeleev akan tetapi sistem
periodik dari Mendeleev Ini juga masih
memiliki beberapa kelemahan dalam sistem
periodik ini terdapat unsur-unsur yang
ditempatkan tidak sesuai dengan kenaikan
massa atom masih terdapat unsur-unsur
yang massanya lebih besar terletak di
depan unsur yang massanya lebih kecil
Selain itu terdapat pula unsur-unsur
yang tidak mempunyai kesamaan sifat
dimasukkan dalam satu golongan
di sisi lain seorang kimiawan Jerman
bernama water Mayer juga meneliti tabel
periodik secara terpisah dari mendelep
Mer mengamati hubungan antara kenaikan
massa atom dengan sifat unsur Hal ini
dilakukan antara lain dengan membuat
kurva volume atom terhadap massa atomnya
berdasarkan grafik tersebut terlihat
bahwa unsur-unsur yang sifatnya mirip
membentuk suatu keteraturan misalnya
unsur logam alkali yaitu natrium kalium
dan rubidium berada dipuncak gas mulia
seperti neon argon Kripton yang memiliki
sifat mirip berada tepat sebelum unsur
alkali
Hai kemudian Mahir mengembangkan
penemuannya ke dalam bentuk tabel tabel
periodik Meyer tidak hanya mengatur
unsur-unsur dengan bertambahnya berat
atom tetapi juga mengelompokkannya
menurut valensinya
Hai Clara terpaut menemukan muatan
positif dalam inti atom pada tahun
1930-an Henry Moseley menemukan nomor
atom suatu unsur dengan bantuan sinar X
menurut mosley sifat-sifat kimia unsur
merupakan fungsi periodik dari nomor
atomnya artinya jika unsur-unsur
diurutkan berdasarkan kenaikan nomor
atomnya maka sifat-sifat unsur akan
berulang secara periodik susunan
periodik yang disusun oleh mosley
akhirnya berkembang lebih baik sampai
didapatkan bentuk sistem periodik unsur
seperti sekarang ini
Hai demikian video penjelasan tentang
perkembangan sistem periodik unsur
semoga bermanfaat
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