ETHIO BIOLOGY.COM GRADE 9-12

🌕Types Of Substances ✅Matters are nothing but something that has mass and occupies space. ✅ The matter is classified into: ✅Pure substances  ✅Mixtures  ✅ Pure Substances ✅The matter that is made up of only one kind of particle or one kind of atom/molecule is defined as a pure substance. Exams  gold, silver, iron, etc. ✅The pure substances are subdivided into two types 🪐Elements  is a subdivision of the pure substance which is made of a single kind of atom and can not be further broken down into a much simpler substance. ✅The elements are further classify in to: ✅Metals: Metals are elements which easily lose electrons. For Example: aluminium, iron etc. They are lustrous, good conductors, malleable, ductile and sonorous. ✔️Non- Metals: Non metals are elements which easily gain electrons to become stable. Example, oxygen, chlorine. metals are non-lustrous, easily breakable, have low density etc. ⭐️Metalloids : the elements which possess the properties of both metals as well as non metals are called metalloids. Example, silicon, boron etc. they are basically called amphoteric in nature. ⭐️Noble gases: noble gases are those elements which do not react and have completely filled the outermost shell. For Example: neon, argon etc. 🪐Compounds A compound is a type of pure substance which is formed chemically by the combination of two or more substances but in a fixed proportion. Compounds  divided into:  ⭐️Organic : organic substances are those substances which are formed by combination of carbon-hydrogen bonds.  ⭐️Non-Organic: non organic compounds are the one which do not have the carbon-hydrogen bonding. 🌕Mixtures are the type of matter which form by mixing more than one kind of atom, particle, or substance. Types of mixtures 🔇 Homogeneous mixtures are the mixtures in which the different substances are mixed together but uniformly. 🌟Heterogeneous mixtures are those mixtures in which the different substances are mixed but the composition is not uniform throughout. https://t.me/EthioBiology

A giant ship's engine broke down and no one could repair it, so they hired a Mechanical Engineer with over 30 years of experience. He inspected the engine very carefully, from top to bottom. After seeing everything, the engineer unloaded his bag and pulled out a small hammer. He knocked something gently. Soon, the engine came to life again. The engine has been fixed! A week later the engineer mentioned to the ship owner that the total cost of repairing the giant ship was $20,000. "What?!" said the owner. "You did almost nothing. Give us a detailed bill." The answer is simple: Tap with a hammer: $2 Know where to knock and how much to knock: $19,998 The importance of appreciating one's expertise and experience...because those are the results of struggles, experiments and even tears. If I do a job in 30 minutes it's because I spent 20 years learning how to do that in 30 minutes. You owe me for the years, not the minutes.