MindMap Gallery The secret of matter
The mind map of the mysterious composition of chemical substances in the eighth grade book introduces the composition of atoms, Representation of elements, material composition, etc. It’s free! !
Edited at 2024-02-11 12:17:12This infographic, created using EdrawMax, outlines the pivotal moments in African American history from 1619 to the present. It highlights significant events such as emancipation, key civil rights legislation, and notable achievements that have shaped the social and political landscape. The timeline serves as a visual representation of the struggle for equality and justice, emphasizing the resilience and contributions of African Americans throughout history.
This infographic, designed with EdrawMax, presents a detailed timeline of the evolution of voting rights and citizenship in the U.S. from 1870 to the present. It highlights key legislative milestones, court decisions, and societal changes that have expanded or challenged voting access. The timeline underscores the ongoing struggle for equality and the continuous efforts to secure voting rights for all citizens, reflecting the dynamic nature of democracy in America.
This infographic, created using EdrawMax, highlights the rich cultural heritage and outstanding contributions of African Americans. It covers key areas such as STEM innovations, literature and thought, global influence of music and arts, and historical preservation. The document showcases influential figures and institutions that have played pivotal roles in shaping science, medicine, literature, and public memory, underscoring the integral role of African American contributions to society.
This infographic, created using EdrawMax, outlines the pivotal moments in African American history from 1619 to the present. It highlights significant events such as emancipation, key civil rights legislation, and notable achievements that have shaped the social and political landscape. The timeline serves as a visual representation of the struggle for equality and justice, emphasizing the resilience and contributions of African Americans throughout history.
This infographic, designed with EdrawMax, presents a detailed timeline of the evolution of voting rights and citizenship in the U.S. from 1870 to the present. It highlights key legislative milestones, court decisions, and societal changes that have expanded or challenged voting access. The timeline underscores the ongoing struggle for equality and the continuous efforts to secure voting rights for all citizens, reflecting the dynamic nature of democracy in America.
This infographic, created using EdrawMax, highlights the rich cultural heritage and outstanding contributions of African Americans. It covers key areas such as STEM innovations, literature and thought, global influence of music and arts, and historical preservation. The document showcases influential figures and institutions that have played pivotal roles in shaping science, medicine, literature, and public memory, underscoring the integral role of African American contributions to society.
The secret of matter
composition of atoms
The composition of atoms:
Atom (non-electroelectric)
Nucleus (positively charged)
Proton (a proton carries one unit of positive charge)
Neutron (uncharged)
Electron (an electron carries one unit of negative charge)
Atomic mass calculation
Electrons in atoms (see example on the right)
element
Elements and element symbols
Made of elements
Pure substances composed of the same element
A pure substance composed of two or more elements is a compound
element symbol
In order to facilitate communication, it is internationally stipulated that each element is expressed by a unified symbol. This symbol is called an element symbol.
periodic table of elements
The periodic table of elements was created in 1869 when the Russian chemist Mendeleev arranged the 63 elements discovered at that time from smallest to largest to form the original periodic table of elements.
Representation of material composition
Chemical formulas and their meanings
A formula consisting of element symbols and numbers representing substances is called a chemical formula
An element can be from:
Explain macroscopically
explain microscopically
Valence
Valence represents the number of electrons gained and lost by atoms when they combine with each other.
Valence is also a property that an element exhibits when forming a compound
Notice!
1. In a compound, calculate the valence of the specified element based on the sum of the positive and negative valence algebras being zero.
2. Clearly mark the valence of the element directly above the element, always with a positive or negative sign.
3. When oxygen appears, the oxygen element is written next.
4. In compounds composed of metals and non-metals, when writing chemical formulas, the element symbols of the metal elements are written in front and the element symbols of non-metal elements are written in the back.
Quantitative representation of material composition