Points explained
Meaning of the word “stable”
Reactions of the alkali metals with chlorine
Reactions of the alkali metals with water
Reactions of the alkali metals with hydrogen
Flame test for Li+
, Na+ and K+
Summary of chemistry of the alkali metals
7.6 The Halogens
7.6.1 Physical properties of the halogens
7.6.2 Covalent bonding in the halogens
Defining a covalent bond
Differences between covalent and ionic bonding
7.6.3 Boiling points and melting points of the halogens
7.6.4 Atomic radii and volumes
7.6.5 Chemistry of the halogens
Reactions with the alkali metals
Summary
7.6.6 Chemistry of the halide ions
The halides are stable
Test for the halide ions
Relative reactivity of the halogens
7.7 Hydrogen - A Family by Itself
7.7.1 Physical properties
7.7.2 Chemistry of hydrogen
Reaction with the alkali metals
7.8 The Third-row Elements
7.8.1 Physical properties of the third-row elements
7.8.2 Compounds of the third-row elements
The hydrides
The chlorides
The oxides
Summary
7.9 The periodic table: chemical reactivity
🔬Understanding Stability, Alkali Metals & Halogens
📚Pre-Requisite Questions:
What does it mean for an element to be "stable"? 🤔
What happens when alkali metals react with chlorine? 🧪
Can you describe the flame test results for Li+, Na+, and K+? 🔥
Break for Reflection 🤔✍️
(Answers: 1. A stable element has a full outer electron shell and doesn't tend to react. 2. When alkali metals react with chlorine, they form ionic salts. 3. Li+ burns with a crimson flame, Na+ with a yellow flame, and K+ with a lilac flame.)
🚀 Lesson Begins!
🧱 Meaning of the Word “Stable”
In the chemistry world, "stable" doesn't mean standing still! It means an atom has a full outer shell of electrons and is not looking to react. They're like that chill friend who's content with what they have! 😌
💥Reactions of the Alkali Metals
💦With Water
Splash alert! Alkali metals react violently with water, producing heat, hydrogen gas, and an alkali metal hydroxide. Think of it as a bath bomb that's too explosive for the tub! 🛀💣
🎈With Hydrogen
Pairing up! Alkali metals can combine with hydrogen to form metal hydrides, releasing energy in the process. It's like an energetic dance duo! 💃🕺
🔥Flame Test for Li+, Na+, and K+
Ready for some fireworks? 🎆 In the flame test, Li+ produces a red/crimson flame, Na+ gives a yellow flame, and K+ presents a lilac flame. It's like a mini festival of lights in the lab! 🎇
7.6 The Halogens
The Halogens, just like the Alkali Metals, are an interesting bunch. They're like the goths of the periodic table, always looking to gain an electron to achieve stability. 🕶️💀
🧪Covalent Bonding in the Halogens
Halogens form covalent bonds by sharing electrons. Imagine sharing your favorite pizza with a friend—that's how halogens share electrons to become stable. 🍕❤️
🔥Boiling Points and Melting Points of the Halogens
Halogens have higher boiling and melting points as we move down the group, thanks to the increasing number of electrons which cause stronger intermolecular forces. It's like adding more logs to the fire—the more you have, the higher the flame! 🏕️🔥
⚖️Atomic Radii and Volumes
Atomic radii also increase as we go down the group. It's kind of like siblings—the older ones tend to be bigger! 🧑🤝🧑
🔥Chemistry of the Halogens
Halogens are pretty reactive. Their reactions with alkali metals form ionic salts, and they're not shy about displacing less reactive halogens. It's like a game of musical chairs! 🎶🪑
7.7 Hydrogen - A Family by Itself
Hydrogen is unique. Despite being the lightest and simplest element, its properties don't quite fit into any group. So, it charts its own path—just like a lone wolf. 🐺⛰️
7.8 The Third-row Elements
The third-row elements are like the middle kids of the periodic table. They have their quirks and surprises! So, let's dive deeper into their physical properties and compounds. 🏊♂️🌊
7.9 The Periodic Table: Chemical Reactivity
The periodic table is not just a chart; it's a tale of reactivity, trends, and atomic friendships. Keep exploring, keep learning! 🚀
Review Questions:
What is meant by a stable element? a. It has a full outer electron shell b. It has no protons c. It is radioactive d. None of the above
What happens when alkali metals react with water? a. Nothing b. They dissolve c. They produce heat and hydrogen gas d. They turn into halogens
Which element doesn't fit well into any group in the periodic table? a. Hydrogen b. Helium c. Oxygen d. Nitrogen
Which of the following is NOT a property of the halogens? a. They form ionic bonds b. They form covalent bonds c. They have high boiling and melting points d. They are very reactive
(Answers: 1. a, 2. c, 3. a, 4. a)
End of Lesson 3
⭐Keep studying, keep learning!⭐