What type of reaction does the following equation represent?

AgNO3 + NaCl ---> AgCl + NaNO3

A. Single-displacement reaction
B. Synthesis
C. Combustion
D. Double-displacement reaction

Covalent bonding (with an electronegativity difference below 0.5) results when fluorine bonds with

A. hydrogen
B. potassium
C. iodine
D. fluorine

Wouldn't the answer be obvious if you took the different between F and F; i.e., the electronegativity of F is 4.0 so 4.0-4.0 = 0 and that's < 0.5, right?

You can calculate, just for the fun of it, the others.
EN H is 2.1
EN K is about 0.8 or 0.9 (you can look it up)
EN I is about 2.7
So HF would be 4.0-2.1 = ?
KF would be 4.0-0.8 = ?
KI would be 4.0-2.7 = ?
F2 would be 4.0-4.0 = 0

What element has the electron configuration 1s22s22p63s23p2?

A. Scandium
B. Phosphorus
C. Krypton
D. Arsenic

Don't run the numbers together.

1s2 2s2 2p6 3s2 3p2 = ?
Add the electrons and that must the be atomic number of the element on the periodic table.

i come up with 16 electrons which would be sulfur

bu that's not one of the options

never mind i figured it out

Based on silicon position on the periodic table, it has

A. 14 electrons, which include 2 valence electrons in the third energy level and 12 electrons distributed over the first two energy levels.
B. 14 electrons, which include 4 valence electrons in the third energy level and 10 electrons distributed over the first two energy levels.
C. 14 valence electrons distributed over three energy levels
D. 14 electrons, which include 10 valence in the second energy level and 4 electrons in the first energy level

which of the following is true regarding the inner transition elements?

A. their valence electrons can be located in both s and f sublevels
B. They occupy the d block of the periodic table
C. These include the lanthanides and actinides and do not have f sublevels

D. These include all elements in groups 3-12