The valence of the "C" atom is a four-valence, which is two single bonds and one double bond, and a total of four bond lines, and is a valence of "C". At this point, the rearrangement and self-inspection are completed, and the layout of the layout is left empty. Office sofa is a common type of chair furniture in the office, providing employees with a comfortable working environment and rest space. According to different functions and design styles, office sofas can be divided into multiple categories. Fabric Sofa,Leather Sofa,Business Sofa,Visitor Sofa Foshan Shengshi Zhihui Technology Co., Ltd. , https://www.sshotelfurniture.com
Self test method:
1) Check the valences in the structural formula based on the valences of atoms and atom groups;
2) Determine atoms and atom groups by valence bonds.
According to the structural formula of the rearrangement, there are only one key and two bond lines in the corners 1, 2, 3, and 4 of the hexagonal ring on the left, which are: 
4 Conclusion
The processing of leaving blank layouts is a difficult point in teaching. The mastering of the processing of the tail-end blank layout is an important part of improving the layout quality of the book layout. Teaching methods that combine basic knowledge and commentary commands can help students better master the processing of the tail-ending blank layout and achieve good teaching results.
1. Classification by Function
1) Rest sofa: The rest sofa is designed to provide a place for employees to rest and relax. It usually uses soft materials and comfortable seat cushions to provide a comfortable sitting posture and support. Rest sofas are usually large and can be used by multiple people simultaneously, sometimes equipped with armrests and backrests to provide better support and comfort.
2) Reception sofa: A reception sofa is a place used to receive visiting guests, usually placed in the reception area of the office. It generally adopts a simple and elegant design style, paired with a fashionable appearance and comfortable seat cushions, to leave a good impression on visitors.
3) Conference sofa: A conference sofa is a chair furniture used in office meeting rooms. It usually adopts a minimalist design style, paired with comfortable cushions and support to provide a comfortable meeting environment. Conference sofas are usually large and can be used by multiple people at the same time. Sometimes, they are also equipped with a desktop and socket, making it convenient for attendees to discuss and use electronic devices.
2. Classified by design style
1) Minimalist style sofa: Minimalist style sofas are characterized by simple, clear lines and simple shapes, emphasizing functionality and practicality. It usually adopts neutral tones and simple design elements, suitable for modern office decoration styles.
2) European style sofa: European style sofas are characterized by luxurious and exquisite decorations and curved shapes, giving people an elegant and romantic feeling. It usually uses delicate carvings and patterns, suitable for traditional or luxurious office decoration styles.
3) Modern style sofa: Modern style sofas are characterized by a simple and fashionable design, emphasizing smooth lines and practical functions. It usually adopts simple geometric shapes and neutral tones, suitable for modern office decoration styles.
Disposal of the "Leaving Tail" Problem in the Layout of Books and Periodicals
At first glance, the structural formula of phthalic anhydride after reforming is different from the manuscript. From the original 10 words to 5 words high, the H, C, CH atoms and atomic groups on the left are gone. There are only single and double bond lines. The right double button changes from vertical to horizontal. After a closer look, its chemical properties have not changed. The method on the left is a method of omitting straight bonds, C, CH atoms, and atom groups in accordance with 3, from complete to simple; the right double bond is according to the chemical bond layout direction of 2 from S, X to Y. After reorganizing the structure, whether it is correct, and then self-check.
Their valence is 3, which is "CH". why? Because of the short form, the "CH" in the corner is omitted, and the "CH" valence is 3 price. Corners 5 and 6 also have single and double bond lines, which are
Their valence is four, which is "C", because the "C" atom in the rear corner is omitted, and the valence of "C" is four. Look to the right again: