1 of 7 Boardworks Ltd 2009 What is ionization energy? Ionization is a process in which atoms lose or gain electrons and become ions. The first ionization (I1) energy of an element is the energy required to remove one electron from a gaseous atom. M(g) M+(g) + e-(g) The second ionization (I2) energy involves the removal of a second electron: M+(g) M2+(g) + e-(g) Looking at trends in ionization energies can reveal useful evidence for the arrangement of electrons in atoms and ions. 2 of 7 Boardworks Ltd 2009
Definitions of ionization energy 3 of 7 Boardworks Ltd 2009 Plotting the successive ionization energies of magnesium clearly shows the existence of different energy levels, and the number of electrons at each level. 6 Successive ionization energies increase as more 5 electrons are removed. 4 3
ionization energy Evidence for energy levels Large jumps in the ionization energy reveal where electrons are being removed from the next principal energy level, such as between the 2nd and 3rd, and 10th and 11th ionization energies for magnesium. electron removed 4 of 7 Boardworks Ltd 2009
More evidence for energy levels first ionization energy (kJ mol-1) The first ionization energies of group 2 elements also show evidence for the existence of different principal energy levels. Even though the nuclear charge increases down the group, the first ionization energy decreases. 900 800 700 600
500 400 Be 5 of 7 Mg Ca Sr element This means that electrons are being removed from successively higher energy levels, which lie further from the nucleus and are less attracted to
Ba the nucleus. Boardworks Ltd 2009 Trends in first ionization energies 6 of 7 Boardworks Ltd 2009 Energy levels 7 of 7 Boardworks Ltd 2009
It is a subset of the whole collection in this file. Chapter 2 Understanding User Interaction Chapter Overview Problem space Conceptual models Interface metaphors Interaction paradigms Conceptual models and physical design Motivation Good intentions are not sufficient to develop good...
To protect the body and clothing from chemicals. plastic gloves . To protect the hands from chemicals and pathogens (things that make you sick). ... test tube clamp . Used to hold test tubes over a burner flame or to...
As there is not enough creep coefficients for ODS steel (12YWT), and the thermal creep of the ODS steel is not included. (Yu's creep data only at T=650 ᵒC and σ=160 MPa) Only F82H material will be considered in the...
Testbed programing. Automation and Robotics. ... Cannot already be a ROBOTC "Reserved Word (while, motor, task, left, right, etc.) ... If-Else Statement. This is an expansion of the IF statement. The IF section still runs the commands inside the ()
Political/Economic Reforms. Emperor Diocletian. Established a tetrarchy. ... Gregorian Chant named after him. ... How did the split btwn the Eastern Orthodox Church and the Roman Catholic Church affect the future of the Byzantine Empire?
Introduction to structural equation modeling Ned Kock SEM techniques Structural equation modeling (SEM) techniques can be: Covariance-based - e.g., those employed by the statistical software analysis tool called LISREL.