Revision topic 3
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
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By who was the periodic table developed?
Dmitri Mendeleev
How did Mendeleev arrange the elements in the periodic table
by putting them in order from their atomic masses
Why didn’t people believe Mendeleev
because he left gaps in his periodic table, he had some elements here that don’t belong like the noble gas argon with the alkali metals, he also wasn’t a proven scientist making people doubtful of him
what are the metals in the first group called?
alkali metals
what are the properties of group 1 alkali metals
• they are very reactive to the point where they are stored under oil to stop them from reacting with oxygen • very soft that they can be cut by a knife easily • the have very low density where they can float on water • they have low melting and boiling points • they don’t conduct electricity • they have shiny silvery surfaces.
explain the chemical properties of alkali metals
they have 1 electron on their outer shell meaning that they need to lose 1 electron to gain a stable (noble gas) structure making them very reactive
what happens when group 1 alkali metals react with water
the basic features are that they would float on the water, they would produce fiz that shows that hydrogen is being formed, and if the metal is very reactive it can cause an explosion or catch fire what is formed is metal hydroxide and hydrogen
what other reactions does group 1 alkali metals have
reacting vigorously with non-metals such as chlorine gas, to produce metal chlorides that are white solids that become colorless when dissolved in water
what are transition metals properties
• good conductors of heat and electricity • they are hard and strong • they have high melting and boiling points • they are shiny and silvery • they have high densities • very unreactive
the transitional metals have different colored compounds depending on…
the number of ions with would have
what are halogens?
they are group 7 elements, they are poisonous non-metal that have different colored vapors.
how does displacement reactions work with halogens
less reactive halogens get displaced by higher reactive halogens in chemical equations
explain why group 1 elements get more reactive as you go down the periodic table
as you go down group 1 the reactivity increases because the electronic shielding increases making the electrostatic force between the negative outer shell electrons and the positive protons in the nucleus get weaker making it easier to lose electrons
explain why group 7 elements get more reactive as you go up the periodic table
as you go up group 7 the reactivity increases because the electronic shielding decreases making the electrostatic force between the negative outer shell electrons and the positive protons in the nucleus get stronger making it easier to gain electrons