Periodic Table
CN → US| HS Code | Tariff Rate | Origin | Destination | Doc |
|---|---|---|---|---|
| 4906000000 | 17.5% | CN | US | Official Doc |
| 4901999000 | 0.0% | CN | US | Official Doc |
AI Analysis
The Periodic Table of Elements is a tabular display of the chemical elements. It is fundamental to modern chemistry, physics, and other sciences. It lists all known chemical elements organized by their atomic number (number of protons), electron configuration, and recurring chemical properties.
Here is a comprehensive overview:
1. Structure of the Periodic Table
- Rows (Periods): There are 7 periods. Elements in the same period have the same number of electron shells.
- Columns (Groups): There are 18 groups. Elements in the same group generally have similar chemical properties because they have the same number of valence electrons.
- Blocks: The table is divided into blocks based on the subshell in which the last electron resides:
- s-block: Groups 1–2 (plus Helium)
- p-block: Groups 13–18
- d-block: Groups 3–12 (Transition Metals)
- f-block: Lanthanides and Actinides (placed below the main table)
2. Key Categories of Elements
| Category | Description | Examples |
|---|---|---|
| Alkali Metals | Group 1; highly reactive metals | Lithium (Li), Sodium (Na), Potassium (K) |
| Alkaline Earth Metals | Group 2; reactive metals | Magnesium (Mg), Calcium (Ca) |
| Transition Metals | Groups 3–12; often form colored compounds | Iron (Fe), Copper (Cu), Gold (Au) |
| Post-Transition Metals | Left of the metalloid line | Aluminum (Al), Tin (Sn) |
| Metalloids | Semi-conductors; properties between metals and non-metals | Silicon (Si), Germanium (Ge) |
| Nonmetals | Poor conductors; gain electrons in reactions | Carbon (C), Nitrogen (N), Oxygen (O) |
| Halogens | Group 17; highly reactive nonmetals | Fluorine (F), Chlorine (Cl), Bromine (Br) |
| Noble Gases | Group 18; inert, non-reactive gases | Helium (He), Neon (Ne), Argon (Ar) |
| Lanthanides | f-block elements (Atomic #57–71) | Cerium (Ce), Europium (Eu) |
| Actinides | f-block elements (Atomic #89–103) | Uranium (U), Plutonium (Pu) |
3. Important Trends
- Atomic Radius: Decreases across a period (left to right) due to increased nuclear charge pulling electrons closer. Increases down a group.
- Ionization Energy: Increases across a period. Decreases down a group.
- Electronegativity: Increases across a period. Decreases down a group. Fluorine is the most electronegative element.
- Metallic Character: Decreases across a period. Increases down a group.
4. Historical Context
- Dmitri Mendeleev (1869): Often credited with creating the first widely accepted periodic table. He arranged elements by atomic mass and left gaps for undiscovered elements, predicting their properties with remarkable accuracy.
- Henry Moseley (1913): Later corrected the table by arranging elements by atomic number rather than atomic mass, resolving inconsistencies.
5. Current Status
- As of 2024, 118 elements have been officially discovered and named.
- The first 94 occur naturally on Earth; elements 95–118 are synthetic.
- The most recent elements added to the table were Nihonium (Nh, 113), Moscovium (Mc, 115), Tennessine (Ts, 117), and Oganesson (Og, 118), confirmed in 2015–2016 and named in 2016.
6. Visual Representation (Simplified)
text 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La-Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac*Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
(Lanthanides and Actinides are typically shown below the main table)
Why It Matters
The Periodic Table is not just a list; it’s a tool for predicting behavior. If you know an element’s position, you can predict its reactivity, bonding preferences, physical state, and many other properties. It is essential for chemistry students, researchers, engineers, and industries ranging from pharmaceuticals to semiconductors.
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About HS Code Classification
The Harmonized System (HS) is an internationally standardized nomenclature developed by the World Customs Organization (WCO) to classify traded products. Over 200 countries use the HS system as the basis for customs tariffs, trade statistics, and import/export regulations.
Each HS code follows a hierarchical structure:
- Chapter (2 digits) — Broad category of goods (e.g., Chapter 84: Machinery and Mechanical Appliances)
- Heading (4 digits) — More specific grouping within the chapter
- Subheading (6 digits) — Internationally standardized breakdown, used by all WCO member countries
- National subdivisions (8-10 digits) — Country-specific extensions for further classification, such as US HTSUS 10-digit codes
Correct HS code classification is essential for smooth customs clearance, accurate duty payment, and compliance with trade regulations. Misclassification can lead to customs delays, overpayment of duties, or penalties.
When importing from CN to US, the applicable tariff rates may include:
- Most-Favored-Nation (MFN) rate — The standard duty rate applied to WTO members
- General rate — Applied to countries without trade agreements
- Trade remedy duties — Additional tariffs such as Section 301 (anti-dumping), Section 232 (national security), or countervailing duties
The information provided on this page is for reference purposes only. For official classification, please consult with your local customs authority or a licensed customs broker.