Answer:
Rb > K > Na > Li
Explanation:
Ionization energy increases up the period and up the group.
From the periodic table, we can see that Li is the going to have the highest ionization energy and Rb is going to have the lowest.
Therefore, the correct answer is the first choice
Barium forms cation : Ba²⁺
<h3>Further explanation</h3>
Given
Barium element
Required
Ion type
Solution
Barium with the symbol Ba is an alkaline earth metal element having the atomic number 56
Electron configuration of Barium: [Xe] 6s2
If we look at this configuration, then Barium will try to achieve stability by removing 2 electrons so that the electron configuration is the same as the noble gas Xenon (Xe)
Because it removes 2 electrons, Barium has the number of protons> the number of electrons so that the charge is positive and forms a cation
Answer:
We need 1.1 grams of Mg
Explanation:
Step 1: Data given
Volume of water = 78 mL
Initial temperature = 29 °C
Final temperature = 78 °C
The standard heats of formation
−285.8 kJ/mol H2O(l)
−924.54 kJ/mol Mg(OH)2(s)
Step 2: The equation
The heat is produced by the following reaction:
Mg(s)+2H2O(l)→Mg(OH)2(s)+H2(g)
Step 3: Calculate the mass of Mg needed
Using the standard heats of formation:
−285.8 kJ/mol H2O(l)
−924.54 kJ/mol Mg(OH)2(s)
Mg(s) + 2 H2O(l) → Mg(OH)2(s) + H2(g)
−924.54 kJ − (2 * −285.8 kJ) = −352.94 kJ/mol Mg
(4.184 J/g·°C) * (78 g) * (78 - 29)°C = 15991.248 J required
(15991.248 J) / (352940 J/mol Mg) * (24.3 g Mg/mol) = 1.1 g Mg
We need 1.1 grams of Mg
Bright Line Emission Spectrum: As the excited electron returns to ground state (it's lower energy level) the energy it originally absorbed is released as discrete lines of light.
Answer:
those are all physical changes and most physical changes can be undone like crushing a pice of metal you can flatten it back out you anwser is physical change
Explanation:
