Unit A.2 Science 10 Flashcards
What are the 6 properties of metals?
- Shiny/Lustre
- Malleable & Ductile
- Silver/grey in color
- Good conductors of electricity & heat
- Most metals are solid at room temp (25c)
- Some metals react strongly with other substances
How many elements are there and how many naturally occurring ones?
There are 115 basic elements, 90 are natural, 25 are manmade/synthetic
What 3 classes are elements divided into?
Metals, Non-metals & metalloids
What is the exception metal that isn’t solid at room temp
Mercury, it melts at -39C
What does inert mean and what are 2 metals that are like that?
Inert means unreactive and it’s gold and platinum
How many non-metal elements are there?
17
Why are non-metals grouped together?
Because of their lack of resemblance to metals
What is the most stable group in the periodic table
Group 18; the noble gases
What is silicon used for?
Computer chips
Is hydrogen a metal or non-metal?
Non-metal
What are the 5 properties of non-metals?
- Dull
- Brittle
- Poor conductors
- Can be gas, liquid or solid at room temp
- Low melting point
How does the periodic table organize elements?
According to it’s chemical properties
Where are the 3 classes on the periodic table?
Metals of far left, Non-metals on right and Metalloids along the staircase that starts from carbon
Name the 4 group names of the periodic table you should’ve memorized
Group 1: Alkaline Metals
Group 2: Alkaline- Earth Metals
Group 17: Halogens
Group 18: Noble Gases
Who invented the periodic table?
Dimitri Mendeleev in 1872
How are the rows numbered and how are the groups/families numbered?
Rows are horizontal and they go from 1-7
Groups are vertical and they go from 1-18
How much of an atom’s mass does the nucleus account for and why?
The nucleus accounts for 99.9% of an atom’s mass because the rest of the atom is just empty space with electrons in energy levels and they’re vv small
Electron’s take up 99.9% of what of an atom?
The volume
How are electrons held?
The electrons closest to the nucleus is held tightly but the valence electrons are pretty lose
Which electrons have the highest energy level and which has the lowest ones
The one’s farthest from the nucleus has the highest energy level, the one’s closer to nucleus have the lowest energy level
How many electrons can the 1’st, 2nd and 3rd energy level hold
1st = 2 2nd = 8 3rd = 8
What determines how many valence energy levels an atom of an element has?
The number which horizontal row the element is in
What subatomic particle determines what element it is
The protons, if the proton numbers of an element change, then it’s a different element now
What is the atomic molar mass?
Average mass of an element’s isotopes aka. the atomic mass (g/mol)
What are isotopes?
Having different numbers of neutrons of the same element therefore the mass changes
How do you find out what isotope an element is?
Atomic Mass - Protons = Neutrons
Protons + Neutrons = Isotope/Atomic Mass
What does ionization mean?
The process of an atom gaining or losing electrons; results in metals & non-metals forming compounds
What are the 2 ions called and how are they formed?
A cation (positive ion) forms when metals lose electrons A anion (negative ion) forms when a non-metal gains ions
When do most ion formations take place?
When a metal and non-metal forms an ionic compound
In chemistry being more stable = ?
Less reactive