Atoms, Elements and Compounds
The atomic number for Cesium.
55
What is the element found in Group 13, Period 4?
Gallium
Does Magnesium gain or lose electrons when it becomes an ion?
Lose
2,8,8,2
The number of protons in aluminium.
13
The alkali metals around found in which group?
Group 1
What is the charge of an Oxygen ion
-2
How many valence electrons do all of the elements in group 14 have?
The number of electrons in a sodium atom.
11
The noble gases are found in which group?
Group 18
What is the charge of a carbonate ion?
-2
What is the name of the scientist who is credited for creating the modern periodic table?
Mendeleev
The identity and number of atoms present in methane (CH4).
1 x Carbon
4 x Hydrogen
Increase
What is the formula of sodium chloride?
NaCl
Positively charged ions are called what?
Cations
The identity and number of atoms present in CaSO4
1 x Calcium
1 x Sulfur
4 x Oxygen
Why are the elements in Group 1 highly reactive? (HINT: consider the valence electrons)
Elements in Group 1 have only one valence electron. This electron is easily lost and so the elements are considered highly reactive.
What is the formula of Beryllium hydroxide?
Be(OH)2
Negatively charged ions are called what?
Anions