Electrons in an atom can be classified as core electrons and valence electrons. Valence electrons are those electrons which are present in valence shell and participates in bond formation. While, Core electrons are all remaining electrons which are not present in valence shell, hence not take part in bonding.
Atomic number of Selenium (Se) is 34 hence it has 34 electrons with following electronic configuration;
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴
From electronic configuration it is found that the valence shell is 4, and the number of electrons present in valence shell are 6. So,
Core Electrons = Total Electrons - Valence Electrons
Core Electrons = 34 - 6
Core Electrons = 28
Result:
There are 28 core electrons in Selenium.
The name of the covalent compound CCl4 is 'Carbon tetrachloride'.
Hope this helps!
Answer:
1.8g
Explanation:
Initial volume = 43.5ml
Final volume = 49.4ml
Mass = 10.88g
Density = ?
Volume = Final volume - initial volume
= 49.4 - 43.5
= 5.9ml
Density = Mass/volume
Density = 10.88/5.9
= 1.8g/ml
Answer:
31,380 Joules
Explanation:
Given Data:
Mass = m = 100 g
Temperature 1 = = 25 °C
Temperature 2 = = 100 °C
Specific Heat Constant = c = 4.184
Change in Temp. = ΔT = 100 - 25 = 75 °C
Required:
Heat = Q = ?
Formula:
Q = mcΔT
Solution:
Q = (100)(4.184)(75)
Q = 31, 380 Joules
Hope this helped!
~AH1807
