Answer: single replacement reaction, 
Explanation:
A single replacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution.
A general single displacement reaction can be represented as :

As strontium metal is added to aluminum chlorate , strontium being more reactive than aluminium, displaces aluminium atom its salt solution and lead to formation of strontium chlorate and aluminum metal.

Hope this helps!!!! Here is a diagram
The iron will retain its magnetic properties it will still magnetic and sulfur will not gain the magnetic properties so t will not be magnetic
Answer:
+2
Explanation:
Elements in group 2A have 2 valence electrons in their outer shell, so when they bond with other atoms, they are most likely to give away these 2 electrons. With 2 electrons gone, the ion will have a positive charge (since there are now more protons than electrons in the atom).
Answer:
7.90×10²¹ formula units
Explanation:
From the question given above, the following data were obtained:
Mass of Cu(NO₃)₂ = 2.46 g
Formula units of Cu(NO₃)₂ =?
From Avogadro's hypothesis,
1 mole of Cu(NO₃)₂ = 6.02×10²³ formula units
Next, we shall determine the mass of 1 mole of Cu(NO₃)₂. This can be obtained as follow:
1 mole of Cu(NO₃)₂ = 63.5 + 2[14 + (3×16)]
= 63.5 + 2[14 + 48]
= 63.5 + 2[62]
= 63.5 + 124
= 187.5 g
Thus,
187.5 g of Cu(NO₃)₂ = 6.02×10²³ formula units
Finally, we shall determine the formula units contained in 2.46 g of Cu(NO₃)₂. This can be obtained as follow:
187.5 g of Cu(NO₃)₂ = 6.02×10²³ formula units.
Therefore,
2.46 g of Cu(NO₃)₂ =
(2.46 × 6.02×10²³)/187.5
= 7.90×10²¹ formula units
Thus, 2.46 g of Cu(NO₃)₂ contains 7.90×10²¹ formula units